Auto Loan Calculator
Finance & MoneyCar loan calculator with trade-in, negative-equity handling, 50-state sales tax, and honest 36/48/60/72/84-month term comparison. 2026 APR defaults, no signup.. Free, private — all processing in your browser.
APR defaults from Experian State of the Automotive Finance Market (Q4 2025): new-car prime-credit ~6.37%, used-car ~11.26%. State sales-tax rates are state-level base rates from each state's Department of Revenue (as of 2026); localities often add 1–3% on top, and specialty rules (EV credits, out-of-state registration, dealer vs private-party) may change your effective rate. Doc fee defaults ($600) are midrange — California caps at $85, Florida can exceed $900, and individual dealers vary wildly. Shop APRs from your bank, credit union, and captive lender; dealer backend rate markup commonly adds 1–2% over what a direct lender would quote. This is a planning tool, not a loan quote, pre-qualification, or financial advice.
One in three people walking into a dealership to trade a car is upside down on it. 31% of new-vehicle trades in Q2 2025 carried negative equity, averaging $6,754 owed beyond the trade-in's value (Edmunds, MarketWatch April 2026). That $6,754 doesn't vanish when the deal closes. It rolls into the new loan, where it earns interest for the next 60, 72, or 84 months. On a typical used-car rate, $6,700 rolled becomes about $9,200 repaid by the time the loan is done. This calculator shows you that number honestly, instead of hiding it behind a smaller monthly payment.
Everything runs in your browser. Price, down payment, trade-in, state, income — no server sees any of it, no F&I office buys the lead, no email capture. There's no signup. There's no "get pre-qualified in 60 seconds" button. The math is the whole product.
Seven things set this apart from the auto-loan calculators on Bankrate, Edmunds, NerdWallet, Kelley Blue Book, or Capital One Auto Navigator. First, the trade-in section has two fields — value AND amount still owed — so negative equity is a first-class input. When you owe more than the car is worth, the calculator rolls the gap into the new loan principal and shows the extra interest cost on a separate line. Second, the state selector knows which states tax the full price and which tax only the post-trade-in difference. California, Virginia, Maryland, Kentucky, Hawaii, and D.C. tax the full price. Most other states tax only the difference. That distinction can swing sales tax by $500 to $1,500 on a typical deal, and no mainstream calculator surfaces it. Third, the term comparison view puts 36, 48, 60, 72, and 84 months side by side so you can see what the "lower monthly" on 84 actually costs in total interest. 84-month loans were 7.3% of new-car sales in 2019 and 12.8% in March 2026 (JD Power). Fourth, the months-until-positive-equity output tells you when you'd be able to sell or trade without bringing cash to closing, given a typical depreciation curve intersected with the amortization curve. Fifth, dealer fees have honest defaults — $600 doc, $200 title/registration, $100 DMV — editable but visible, unlike calculators that default them to zero and let the monthly look deceptively low. Sixth, the new/used toggle adjusts the default APR (6.37% new / 11.26% used, Experian Q4 2025 prime-credit benchmarks). Seventh, the 20/4/10 rule sanity check flags when your down payment is under 20%, your term is over 48 months, or total transportation spending is over 10% of gross income — Consumer Reports' and Edmunds' conservative ceiling. Not blocking, just honest.
Things the tool won't do. It doesn't pull your credit, doesn't quote specific lender rates, doesn't have vehicle inventory or VIN lookup, and doesn't model EV tax credits (policy changes too frequently to hard-code). Leases have their own math (money factor, residual value, depreciation, acquisition fees) — there's a lease-vs-buy comparison toggle in this tool, but if you're seriously considering a lease first, wait for our dedicated auto-lease calculator rather than treating this one as primary. What this tool does is show you, honestly, what the purchase-financing math actually looks like with all the pieces the F&I office would rather keep off your radar.
Auto Loan Calculator — key features
Negative-equity handling as a first-class input
Trade-in section has two fields: value AND amount still owed on the trade-in loan. When owed exceeds value, the calculator surfaces the negative-equity gap, rolls it into the new loan principal, and shows the extra interest cost on a separate line. Thirty-one percent of new-vehicle trade-ins in Q2 2025 had negative equity, averaging $6,754 (Edmunds). No other calculator on the SERP surfaces this honestly by default.
State-specific sales tax, handled correctly
Seven jurisdictions tax the full sale price regardless of trade-in — California, Virginia, Maryland, Kentucky, Hawaii, D.C., and Michigan within a cap. The other 44 states tax only the difference (sale price minus trade-in). The state selector knows which rule applies and adjusts the taxable base automatically, with citations to each state's Department of Revenue in the tooltip. Most calculators treat sales tax as a flat generic percentage and silently get it wrong.
Term comparison side by side
36, 48, 60, 72, and 84 months in five columns on the same screen. Each shows monthly payment, total interest, total paid, and months-until-positive-equity. You see the lifetime-cost tradeoff of a longer loan instead of just the lower monthly number. JD Power's data shows 84-month loans at 12.8% of new-car sales in March 2026, up from 7.3% in 2019 — they've normalized, which is exactly why the honest comparison matters.
Months-until-positive-equity output
A unique line in the results: 'You'll owe more than the car is worth until month X.' Computed from a typical depreciation curve (15-20% year one, 10-12% year two, 8-10% year three, 6-8% ongoing, per KBB and Edmunds data) intersected with the amortization curve. On an 84-month 10%-down loan, being upside down for 36-42 months is common — that's the timeline you're committing to.
Honest dealer-fee defaults
Doc fee default $600 (ranges $75-$1,500 by state; California caps at $85, Florida averages $600-$900 and has no cap). Title and registration default $200. DMV default $100. All editable. Calculators that default these to zero make the monthly payment look $25-$50/month lower than reality, which is exactly what makes buyers say 'but the calculator said…' at the F&I desk.
New vs used APR context
Toggle shifts the default APR — 6.37% for new, 11.26% for used (Experian Q4 2025 prime-credit benchmarks). A small banner shows the current-quarter average so you can sense-check whether the rate your lender quoted you is competitive. Used-car APRs typically run 3-5 percentage points higher than new-car for the same credit tier; the calculator makes that spread visible instead of letting buyers assume parity.
Lease-vs-buy comparison toggle
Enable the lease panel and enter MSRP, cap cost, residual percentage, money factor (auto-converted to APR at MF × 2400), lease term, and mileage allowance. The tool shows a lease monthly payment side by side with the loan monthly from the main calculator. Honest caveat box calls out the structural differences — lease returns the car and has a mileage cap; finance keeps the car and doesn't. Not a push in either direction, just the math.
20/4/10 rule sanity check
Banner flags when your deal crosses Consumer Reports' and Edmunds' conservative ceiling — down payment under 20%, term over 48 months, or total transportation cost over 10% of gross income. Not blocking, informational. At 2026 car prices and rates, few new-car buyers hit all three gates, which is worth naming honestly instead of pretending the rule is easy to clear.
Runs entirely in your browser
Price, income, trade-in value, amount still owed — none of it leaves your device. No signup, no email capture, no 'get pre-qualified in 60 seconds' modal, no dealer-network lead funnel. Refresh the page and everything's gone. The math is the whole product.
How to use the Auto Loan Calculator
- 1
Pick New or Used
The toggle sets the default APR to 6.37% for new or 11.26% for used (Experian Q4 2025 prime-credit benchmarks). Override with your specific quoted rate if you have one. Used-car rates run higher because used-car loans are riskier for lenders — lower resale value ceiling, more uncertainty about mechanical condition.
- 2
Enter the negotiated price, not the sticker
The number you're actually paying after any incentives, rebates, or negotiation. Don't start with the sticker and trust the calculator to model your rebates — just enter the out-the-door negotiated price. If the dealer is showing a manufacturer cash-back offer, subtract it first. If they're offering a 0% APR promotion, type 0 in the APR field.
- 3
Set down payment and trade-in value
Cash down can be in dollars or a percentage. Trade-in value should be what the dealer is actually crediting — use Kelley Blue Book or Edmunds to get a realistic range before you walk in, and don't assume the dealer's first offer is the best they can do. A $10,000 trade-in might get a $9,000 first offer; the $1,000 negotiation gap is real money over the loan's life.
- 4
Enter the amount still owed on your trade-in
The single most important input for anyone with an existing car loan. If your trade-in is worth $10,000 and you owe $12,000, you have $2,000 in negative equity that will roll into the new loan. The calculator flags this and shows the extra interest cost. Twenty-nine million US drivers carry negative equity on their vehicle (Q2 2025, Edmunds). If that's you, see the number before you sign anything.
- 5
Set APR, term, and state
APR from your lender's quote (shop your bank, a credit union, and the captive — dealer backends typically mark up 1-2% over bank rates on the same credit tier). Term in months; default is 60 because it's the common baseline, but pick what matches your offer. State is used for sales tax rules — the selector handles the full-price-vs-difference distinction automatically.
- 6
Edit doc, title, registration, and DMV fees if you know yours
Defaults are $600 doc, $200 title and registration, $100 DMV — reasonable averages. If your state caps doc fees (California at $85) or the dealer has quoted a specific bigger number, edit to match. Getting these right is worth doing because the fees get financed just like the car — so a $300 doc-fee difference becomes $350-$400 of total repayment over a 6-year loan.
- 7
Read the full breakdown, not just the monthly
The headline monthly is one number. The real story is in the breakdown — financed total (which includes sales tax, fees, and any rolled negative equity), total interest, total paid, and months until positive equity. If the financed total is $8,000 higher than the sticker price, you're looking at a real drive-off cost that's worth pausing on before you sign.
- 8
Check the 20/4/10 banner and term comparison
The 20/4/10 banner flags when down is under 20%, term is over 48 months, or total transportation spending is over 10% of gross income. The term comparison view shows what different lengths actually cost in total interest. If you're stretching to 72 or 84 months to afford the payment, the term comparison makes the alternative — smaller car, higher down, longer saving period — concrete instead of abstract.
Common use cases for the Auto Loan Calculator
Pre-shoppers pricing a specific car
- →Real monthly payment on a specific listing: You've found a car on Cars.com, Edmunds, or Facebook Marketplace. Enter the price, a realistic down, your state, and the current market APR. The calculator gives you the real monthly including sales tax and fees — which is 8-15% higher than the bare principal-and-interest number dealer calculators love to show. Know this number before you walk in.
- →Shop multiple lenders before accepting the dealer's rate: Dealer finance offices typically mark up the captive-lender rate 1-2 percentage points on the same credit tier. Run the calculator at the rate your own bank or credit union quoted you first, then again at whatever the dealer offers. On a $35,000 loan over 60 months, a 1.5% rate difference is about $1,600 in total interest. Use the tool as ammunition for the 'match my bank's rate' conversation.
- →Compare new vs used for the same vehicle segment: Toggle new-vs-used and see how much the APR spread matters. A $35,000 new car at 6.37% for 60 months is about $682/month; a comparable $25,000 three-year-old used version at 11.26% for 60 months is about $546/month. The used car saves about $8,100 in total financing cost, but the APR delta tells you the lender is pricing real risk — used cars have more uncertain resale and mechanical histories. Knowing the APR is part of the deal, not just a number, helps you decide.
Trade-in and negative-equity shoppers
- →Figure out the real cost of rolling negative equity: Your car is worth $10,000. You owe $12,000 on it. You want to buy a $28,000 car. Enter all three numbers and see the $2,000 gap roll into the new loan. At 11.26% used-car APR over 72 months, that $2,000 of negative equity costs about $760 in extra interest. On the national-average $6,754 gap, it's closer to $2,500 extra. If seeing that number makes you want to wait a year and pay down the current loan first, that's the calculator doing its job.
- →Decide whether to keep the current car or trade now: Compare two scenarios: stay in the current loan and pay it down to positive equity (typically 6-18 months depending on amortization progress), or trade now and roll the gap. The tool shows the total interest cost of rolling. Sometimes the wait-and-pay-down option saves $2,000-$4,000 and removes the stuck-in-negative-equity window on the new car. Sometimes the urgency (job change, growing family, current car unreliable) makes rolling worth it. Either way, know the dollar cost of the choice.
- →Model the break-even on a longer term plus negative equity: Some buyers with negative equity stretch to 84-month terms to keep the monthly manageable. The tool shows both costs — the rolled negative-equity interest plus the extended-term interest — stacked. On a deal with $6,000 in rolled negative equity, 84-month 10%-down terms can keep you upside down on the new car for 48 months or more. Knowing that window in advance changes the conversation.
State-specific tax situations
- →Buy a car across state lines and pay the right sales tax: Rule: you pay sales tax in the state where you register the car, not where the dealer is. Out-of-state dealers often collect the delivery-state rate anyway, but your home-state registration process will reconcile. Enter your home state in the calculator to see the right tax for your situation. If the dealer is quoting you a different number, ask specifically which state's tax they're collecting.
- →Understand why California and Virginia feel more expensive: A $40,000 car with an $8,000 trade-in carries $2,000 in sales tax in Texas (6.25% of the $32,000 difference) but $2,900 in California (7.25% of the full $40,000). That $900 gap is why full-price-tax states feel more expensive even when the advertised tax rate is similar. The calculator surfaces this by state, with citations.
- →Check the no-sales-tax states (Delaware, Montana, New Hampshire, Oregon) before you plan a cross-border buy: Four states have no general sales tax. Buying there saves the sales tax dollar-for-dollar. But you pay your home-state tax when you register the vehicle — which is the whole bill if your home state is California, Virginia, Maryland, Kentucky, Hawaii, or D.C. A cross-border shopping trip only saves you tax if you both buy and register in the no-tax state, which requires actually living there. The tool's state selector is for your registration state.
Term-length decisions and long-term planning
- →See what 84 months actually costs before you agree to it: The 84-month term drops the monthly by $100-$200 compared to 60 months, but total interest goes up by $2,000-$5,000 depending on loan size. Plus the positive-equity window extends by 18-24 months. The term-comparison view puts both numbers side by side so the tradeoff isn't abstract. For most buyers, 60 months is the honest ceiling; 72 is a stretch; 84 is a flag.
- →Calculate the real cost of financing a depreciating asset: Unlike a mortgage where the underlying asset typically appreciates, a car depreciates 15-20% in year one and keeps declining. A loan term longer than the car's meaningful useful life (roughly 5-7 years for most vehicles without significant maintenance investment) means you're paying interest on a shrinking asset for years. The months-until-positive-equity line makes this visible — and often argues for a shorter term or a cheaper car.
- →Run the 20/4/10 rule on your actual income: Enter your gross annual income in the affordability fields. The 20/4/10 banner shows pass/fail for each threshold — 20% down, 48-month max term, 10% of gross on total transportation. Not blocking. If you're missing two out of three on a vehicle you want, that's useful information about whether this is a stretch car, a comfortable car, or a budget misfit.
- →Budget-anchored affordability search: Switch to Affordability mode and enter 'I can spend $450/month.' The calculator reverses the math and shows max vehicle price at different terms and down payments. A $450 budget with 20% down and 48-month term supports a much smaller car than the same $450 budget with 84-month term — but the first combination keeps you out of trouble, and the second lands you a car you're still paying for long after you've decided you want something else.
Auto Loan Calculator — examples
Default: new car, $35,000 in California, 60 months
Condition: New Price: $35,000 Down payment: $3,500 (10%) Trade-in: none APR: 6.37% (Experian Q4 2025 new-car prime-credit benchmark) Term: 60 months State: California (7.25% full-price tax) Fees: $600 doc + $200 title/reg + $100 DMV = $900
Sales tax: $2,537.50 (7.25% of $35,000 — CA taxes the full price) Amount financed: $34,937.50 Monthly payment: $681.87 Total interest: $5,974.70 Total paid: $40,912 Months until positive equity: ~14 months 20/4/10 check: FAIL on down (<20%); PASS on term; PASS on transportation at $75k income.
Same car, stretched to 84 months — the term-comparison trap
Same as above, but term: 84 months
Monthly payment: $516.58 (saves $165/mo vs 60-month) Total interest: $8,455.09 (costs $2,480 MORE than 60-month) Total paid: $43,393 Months until positive equity: ~36 months (3x longer than 60-month case) 20/4/10 check: FAIL on down; FAIL on term; PASS on transportation. Verdict: lower monthly, higher lifetime cost, 3 years stuck upside down before positive equity.
Underwater trade-in on a used car in Texas
Condition: Used Price: $28,000 Down payment: $3,000 Trade-in value: $10,000 Amount still owed on trade: $12,000 (= $2,000 negative equity) APR: 11.26% (Experian Q4 2025 used-car prime-credit benchmark) Term: 72 months State: Texas (6.25% difference-tax) Fees: $900 default
Negative equity rolled: $2,000 Taxable amount: $18,000 ($28,000 − $10,000 trade-in; TX taxes the difference) Sales tax: $1,125 Amount financed: $19,025 (includes the $2,000 of rolled negative equity) Monthly payment: $363.68 Total interest: $7,160 Extra interest caused by rolled negative equity: ~$760 over 72 months Months until positive equity: ~18 months on the new car.
Same vehicle, same trade situation, but in California
Same as above but state: California (7.25% full-price tax)
Taxable amount: $28,000 (CA taxes the full price even with trade-in) Sales tax: $2,030 ($905 MORE than the Texas version) Amount financed: $19,930 Monthly payment: $380.98 ($17/month higher than TX case) Verdict: the state-specific trade-in rule alone is a $905 swing on an identical deal. Calculators using a flat sales-tax input silently mislead California and Virginia buyers by this amount every time.
No-sales-tax state: Oregon new car, 60 months
Condition: New Price: $40,000 Down payment: $4,000 (10%) Trade-in: none APR: 6.37% Term: 60 months State: Oregon (0% state sales tax; has a small vehicle privilege tax on dealer purchases not modeled here) Fees: $900
Sales tax: $0 Amount financed: $36,900 Monthly payment: $720.17 Total interest: $6,310 Total paid: $43,210 Months until positive equity: ~14 months Verdict: Oregon, Montana, New Hampshire, and Delaware have no general state sales tax — a meaningful saving on a car purchase if you actually live there. Registering out-of-state to dodge tax doesn't work; home-state tax is paid at registration.
Lease vs buy on a $45,000 luxury sedan, 36-month lease vs 60-month finance
Buy path: MSRP/price: $45,000 | Down: $4,500 | APR: 6.37% | Term: 60 months | State: CA Lease path: MSRP: $45,000 | Cap cost: $44,500 (negotiated slightly below MSRP) Residual: 57% ($25,650 end-of-lease) Money factor: 0.00205 (= 4.92% APR equivalent) Term: 36 months | Cap reduction (cash down): $2,500 Acquisition fee: $695 | Mileage allowance: 10,000/yr
Finance monthly: $851 (owns the car at month 60; car worth ~$22-27K at that point depending on depreciation) Lease monthly: $530 (returns car at month 36; no equity built) Lease-end options: return, buy out at $25,650 residual, or extend Lease mileage cap: 30,000 miles over 3 years — overage is typically $0.15-$0.25/mile after the cap Verdict: lease costs $321/month less, but at lease-end you have no asset and 10,000 miles/year of driving. Finance builds equity but commits you to 60 months of $851 and the car's depreciation risk. Good for: high-mileage drivers lean finance, lower-mileage drivers who always want the newest car lean lease.
Technical details
Auto loan math is the same amortization formula as mortgage or personal loan math: given the amount financed P, monthly rate r = APR / 12, and term n in months, the monthly payment is:
``
monthly = P × (r × (1 + r)^n) / ((1 + r)^n − 1)
The interesting work in an auto calculator isn't the amortization — it's figuring out what P actually is. The "amount financed" at the top of the formula is where the negative-equity, sales-tax, and fee rules collide.
What actually gets financed. Starting from the sticker price, subtract your cash down payment and the trade-in value. If you owe more on the trade-in than it's worth, add the negative-equity gap (what you still owe minus the trade-in value). Add sales tax on the taxable base (which depends on your state's rules — see next section). Add doc fee, title and registration, DMV. Whatever's left is the financed principal:
``
financed = price − down − tradeInValue + negativeEquity + salesTax + totalFees
That's the number the monthly-payment formula runs against. On a $35,000 new car with $3,500 down and no trade-in, California's 7.25% full-price sales tax ($2,537) plus $900 in fees pushes the financed total to $34,937, which at 6.37% for 60 months is about $682/month — not the $608 you'd get if you ignored tax and fees entirely.
State sales tax — the piece most calculators get wrong. Seven jurisdictions (California, Virginia, Maryland, Kentucky, Hawaii, D.C., and Michigan within a cap) tax the full sale price regardless of trade-in. The other states tax only the difference — sale price minus trade-in value. On a $40,000 car with an $8,000 trade-in in Texas (6.25% base, difference-tax state), sales tax is 6.25% × ($40,000 − $8,000) = $2,000. The same deal in California (7.25%, full-price state) is 7.25% × $40,000 = $2,900. That $900 gap is invisible on any calculator that treats sales tax as a single flat percentage of the sale price. Ours handles it per state, with citations to each state's Department of Revenue in the state selector's tooltip.
Negative equity — the math of being upside down. If your trade-in is worth $10,000 but you still owe $12,000 on its loan, the trade-in doesn't reduce what you finance — it adds $2,000 to it. The dealer pays off your old loan and tacks the $2,000 onto the new loan. On a 72-month loan at 11.26% used-car APR, that $2,000 of rolled negative equity costs about $760 in extra interest. On $6,700 (the national average), the extra interest is closer to $2,500. Thirty-one percent of trade-in customers hit this (Edmunds Q2 2025). The calculator shows the negative-equity amount, flags it, and includes the extra interest cost in the financed total — rather than silently folding it into a lower-looking monthly.
The depreciation curve and why "positive equity" matters. A new car loses about 15-20% of its value in year one, 10-12% in year two, 8-10% in year three, and 6-8% per year after that (Kelley Blue Book and Edmunds depreciation data, averaged across segments). An amortization schedule pays down principal slowly at first because most of each early payment is interest. The gap between what you owe and what the car is worth opens in the first few months of a long loan, and on 72- or 84-month loans it can stay open for 3-4 years. "Months until positive equity" is the row that tells you when the two curves cross — when you'd be able to sell or trade without bringing cash to closing. On a 60-month 20%-down loan it's usually month 12-18. On an 84-month 10%-down loan it's often month 36-42. That's the timeline you're committing to when you sign.
Term length and the 84-month trap. Lengthening a loan lowers the monthly payment but raises total interest. On a $35,000 financed balance at 6.37%, the payment at 60 months is about $682 and total interest is about $5,975. At 84 months the payment drops to about $517 but total interest rises to about $8,455 — $2,480 more for $165/month less. Plus the longer negative-equity window: you'd be "stuck" (owing more than the car is worth) longer, and the cost of an unexpected accident, life change, or desire to trade becomes much higher. JD Power's data shows 84-month loans at 12.8% of new-car sales in March 2026, up from 7.3% in 2019 — they're normalized now. That doesn't mean they're wise.
APR vs interest rate. APR is the nominal annual interest rate the calculator uses; Reg Z requires lenders to disclose it so buyers can compare offers across fee structures. For 'what's my payment,' type the APR your lender quoted. For 'is the dealer marking up my rate,' compare APR to APR between lenders — dealership finance backends typically mark up the captive-lender rate 1-2 percentage points above what your own bank or credit union would quote on the same credit tier. Shop the rate first; let the dealer match it, don't let them set it.
The 20/4/10 rule. Down at least 20%, loan term no longer than 48 months, total transportation costs (payment, insurance, fuel, maintenance) no more than 10% of gross income. Consumer Reports popularized it; Edmunds and several financial planners use it as a conservative ceiling. Stricter than most lenders require. The calculator flags violations of any of the three but doesn't block — at 2026's car prices and interest rates, very few new-car buyers hit all three gates, and that's worth naming rather than pretending the rule is always easily achievable.
What the tool doesn't model. Specific manufacturer incentives (cash rebates, 0% APR promotions) that change weekly. EV tax credits (federal and state, frequently updated). Insurance cost variation by state and driver profile. Specific dealer doc-fee caps or surcharges beyond the honest default. Credit-tier APR estimation — the APR you get depends on credit, lender, and loan-to-value, and no calculator can predict it without pulling your credit. Trade-in valuation — use Kelley Blue Book or Edmunds for a realistic number before feeding it into the trade-in value field here.
Common problems and solutions
⚠Ignoring the 'amount still owed on trade-in' input when you have a current loan
Twenty-nine million US drivers carry negative equity on their vehicle (Edmunds Q2 2025). If you owe more on your current car than it's worth, trading it doesn't zero out that debt — it rolls into the new loan. On a 72-month loan at 11.26% used-car APR, $6,700 of rolled negative equity costs about $2,500 in extra interest. Always enter both the trade-in value AND the amount still owed. If the second field is larger than the first, pause on the deal entirely and consider paying down the current loan before trading.
⚠Treating the sticker price as your real monthly payment anchor
Sticker is just the starting number. Real out-the-door on a typical deal adds 6-10% in sales tax (higher in full-price-tax states), $500-$1,500 in doc and DMV fees, and any rolled negative equity. A $35,000 sticker is typically $38,000-$42,000 financed — which changes your monthly payment by $60-$100. Use the financed-total line in the breakdown, not the sticker, when you're deciding what you can afford.
⚠Assuming every state's sales tax works the same way with trade-ins
Seven jurisdictions tax the full sale price regardless of trade-in (California, Virginia, Maryland, Kentucky, Hawaii, D.C., and Michigan within a cap). The other 44 tax only the difference after trade-in. On a $40,000 car with an $8,000 trade in, that's a $900 sales-tax difference between CA and TX on identical rates. Calculators that use a flat generic sales-tax percentage silently tell Californians and Virginians their deal costs less than it does.
⚠Stretching to 72 or 84 months without understanding the negative-equity window
A new car loses 15-20% of its value in year one and keeps declining. An 84-month loan pays down principal so slowly that you can stay upside-down for 36-42 months — more than half the loan's life. During that window, any sale, trade, or total-loss insurance claim leaves you writing a check to the lender for the difference. The term-comparison view shows months-until-positive-equity for each option; if yours is above 24 months, consider whether a shorter term or cheaper car would be smarter.
⚠Accepting the dealer's APR without shopping your own bank or credit union first
Dealer finance offices typically mark up the captive-lender rate 1-2 percentage points on the same credit tier — the markup is the F&I office's profit. On a $35,000 60-month loan, a 1.5% rate difference is about $1,600 in total interest. Get a pre-approval from your bank or a credit union before you step onto the lot. If the dealer's rate beats that, fine. If it's higher, ask them to match the bank's number or walk away from their finance product.
⚠Forgetting used-car APRs run 3-5 points higher than new-car APRs
Used-car loans carry more risk for lenders — lower resale value ceiling, more uncertain mechanical history, wider price variability. Experian Q4 2025 prime-credit averages were 6.37% for new and 11.26% for used. Using the new-car default rate on a used-car deal understates your monthly payment by $40-$80 and your total interest by $2,000-$4,000 over the loan's life. Toggle New/Used correctly, or override with the specific rate your lender quoted.
⚠Trusting the F&I office's 'four-square' worksheet to show you the real deal
The classic dealer four-square worksheet (trade-in, sale price, down payment, monthly payment arranged in a 2x2 grid) is designed to let the finance manager adjust numbers across cells while keeping one 'win' for you visible. Salespeople move around in that grid to hit your monthly-payment target by extending the term, rolling in add-ons, or reducing trade-in value. Use this calculator independently: nail down the price first, then the APR, then the term, separately. Don't let the four-square bundle them into a single monthly-payment negotiation.
⚠Rolling dealer add-ons (extended warranty, paint protection, gap insurance) into the financed balance without modeling their cost
An extended service contract priced at $2,500 financed over 60 months at 6.37% costs about $2,913 in total — plus it typically has a significant dealer markup over the wholesale cost. Most of these products are cheaper purchased separately from a third party, and some (like gap insurance from your car insurer) cost a fraction of the F&I office's number. If you're considering add-ons, run each one as a separate line before signing: what would this cost me in total, over the loan, with interest? Often the answer changes your mind.
⚠Forgetting that registration, insurance, fuel, and maintenance aren't in the monthly payment
Your loan payment is the visible number, but total transportation cost is what your budget actually has to absorb. Insurance varies wildly by state, vehicle class, and driver profile — $100-$300+/month is common. Fuel adds $100-$250/month depending on mileage. Maintenance, especially for older used cars or luxury models, averages $100-$150/month long-term. The 20/4/10 rule's 10% cap is on total transportation, not just the loan payment — check the banner or budget separately for the full picture.
Auto Loan Calculator — comparisons and alternatives
The auto-loan calculator space on the SERP is crowded and each incumbent has a characteristic weak spot worth naming.
Bankrate has a clean, competent calculator with solid amortization math and decent trade-in support. The downside is the sales-tax input is a single generic percentage — no state-specific trade-in rule handling, so Californians and Virginians who use it with a trade-in understate their real sales tax by several hundred dollars. No negative-equity input. Result pages surrounded by lender-affiliate CTAs.
Edmunds is probably the strongest pure auto-shopping destination on the web — calculator, vehicle data, inventory, editorial reviews. The calculator handles trade-in, sales tax, and fees reasonably well. Weaker on the term-comparison and negative-equity angles; they treat 84-month loans as just another option rather than calling out the lifetime-cost difference. Their strength is vertical integration; ours is calculator honesty.
NerdWallet splits the auto-financing question across three tools — auto loan calculator, reverse auto loan calculator, lease buyout calculator — each competent individually but fragmented across URLs. Good editorial content around each. Auto-focused affiliate CTAs are heavy.
Kelley Blue Book and CarFax are primarily vehicle-data destinations, not calculator leads. Their calculators work; they're not the reason people visit either site.
Cars.com and Autotrader are listings-first — calculators exist to serve shoppers already browsing specific vehicles. Fine for that flow; not a destination for standalone calculation.
Capital One Auto Navigator is an excellent product if you're shopping within Capital One's dealer network. The calculator leads into pre-qualification and dealer matching — which is the product. Not our user.
Calculator.net is functionally deep — trade-in, sales tax, extra payments, term comparison. Ugly UI, dense ad footprint, no state-tax sophistication, no negative-equity modeling, no plain-English 84-month critique, no 20/4/10 rule check. Power users happy; casual users confused.
Big-bank calculators (Chase, Wells Fargo, Ally, Bank of America) are basic payment math with strong "apply for a loan" CTAs. Exist to funnel applicants.
Our version leans in the opposite direction: negative equity is a first-class input, state sales-tax rules are modeled correctly, term comparison is visible by default, months-until-positive-equity is a headline output, dealer fees have honest defaults, and the 20/4/10 banner flags when your deal crosses conservative thresholds. Nothing clickable beyond the tool itself. No lender funnel. No inventory. No signup.
The tradeoffs we made, honestly:
- No vehicle inventory or valuation. We don't have listings and don't pretend to. Use Edmunds or Kelley Blue Book for realistic trade-in values and retail pricing before feeding numbers into this calculator.
- No credit-tier APR estimation. Your APR depends on credit, LTV, lender, and product — we use Experian Q4 2025 prime-credit benchmarks (6.37% new / 11.26% used) as defaults and let you override. Shop at least three lenders (your bank, a credit union, the captive) for a real quote.
- No dealer-network quotes or pre-qualification. Capital One Auto Navigator and LendingTree own that space. We don't.
- No manufacturer incentives or rebates baked in. Cash-back offers and 0% APR promotions change weekly — hardcoding them would go stale fast. Type your specific negotiated price after incentives.
- No EV tax credit modeling. Federal and state EV incentives change frequently and have eligibility requirements we can't verify without pulling buyer data. Check fueleconomy.gov for federal credit status and your state's Department of Revenue for state incentives.
- Leases as a secondary toggle only. The lease-vs-buy comparison inside this tool uses the same money-factor and residual-value math a dedicated lease calculator would, but the UX is purchase-financing first. If you're primarily considering a lease, our dedicated auto-lease calculator (on the roadmap) will be the better home for that flow.
- No insurance cost modeling. Insurance quotes depend on state, driver profile, and vehicle class in ways we can't predict. Get quotes from two or three insurers before finalizing a car decision — the cost delta between similar vehicles can be larger than you expect, especially for luxury or sports models.
For the default case — price, down, trade-in (including negative equity), state tax, term, fees — this is the honest monthly payment with all the pieces in view. For anything past that, we'll happily name the specialist tool or the real professional that fits.
Frequently asked questions about the Auto Loan Calculator
▶How much car can I afford on a $75,000 salary?
Depends on your debts, down payment, and lifestyle. As rough anchors at 6.37% new-car APR and 60-month terms with $0 trade-in and $900 in fees: $400/month budget supports about a $20,000 car. $500/month supports about $26,000. $650/month supports about $35,000. The 20/4/10 rule says total transportation (payment + insurance + fuel + maintenance) should stay under 10% of gross — on a $75,000 salary, that's $625/month for everything, which typically maps to a loan payment of $400-$450. Run your specific numbers through the Affordability mode for your exact situation.
▶What's a good auto loan rate in 2026?
Experian's State of Auto Finance Q4 2025 reported prime-credit average APRs of 6.37% for new cars and 11.26% for used. Sub-prime borrowers see 13-20% on new and 18-25% on used. A good rate is at or below the Experian average for your credit tier. If you have 740+ credit, you should be at or near the prime benchmark — if a dealer is quoting you meaningfully above that, they're marking up over the captive-lender rate, and your own bank or credit union will likely beat them.
▶Is 84 months too long for a car loan?
Conservative opinion: yes. The loan outlasts most cars' peak reliability, leaves you upside down on the vehicle for 3-4 years, and costs thousands more in total interest for the sake of $100-$200/month lower payment. JD Power reports 84-month loans at 12.8% of new-car sales in March 2026 — common, but common doesn't mean wise. If you can't afford the car on a 60-month loan, the honest move is a cheaper car or a larger down payment, not a longer term. The term-comparison view shows the lifetime cost gap explicitly.
▶What's negative equity and how do I know if I have it?
Negative equity means you owe more on your car loan than the car is currently worth. Common after long loan terms, low down payments, heavy first-year depreciation, or any combination. To check: get a realistic trade-in value from Kelley Blue Book or Edmunds, then subtract your current loan balance. If the number is negative, you're upside down by that amount. As of Q2 2025, 31% of new-vehicle trade-ins were underwater (Edmunds), averaging $6,754 in gap. If that's you, entering both values in this calculator's trade-in section shows the real cost of rolling it forward.
▶Is it bad to roll negative equity into a new car loan?
It's expensive and common. On a 72-month loan at 11.26% used-car APR, $6,700 rolled adds about $2,500 in extra interest over the loan's life. You also start the new loan already upside down, which extends the positive-equity window. The calculator shows both costs honestly. The less bad alternatives: pay down the current loan for 6-12 months before trading, buy a cheaper car so the rolled equity is a smaller percentage of the new loan, or sell the current car privately (which usually fetches more than trade-in value and lets you pay off the loan directly). None of these are as convenient as rolling, but each can save thousands.
▶How much should I put down on a car?
20% is the conservative rule — Consumer Reports' 20/4/10 framework puts it at that level to ensure you're not upside down immediately given typical first-year depreciation. In practice, 10% is the common minimum for good terms, and many lenders will do 0% down for prime-credit borrowers (which is usually a bad idea given depreciation). Putting more down reduces the loan balance, cuts total interest, and keeps you out of negative-equity territory. For a $35,000 new car, 20% down is $7,000 — significant money, but worth it if you have it.
▶Should I finance through the dealer or my own bank?
Get a pre-approval from your bank or a credit union before you go to the dealer. Dealer finance offices typically mark up the captive-lender rate 1-2 percentage points as their profit margin. On a $35,000 60-month loan, that markup is ~$1,500 in total interest. Once you have your pre-approved rate in hand, let the dealer try to beat it — sometimes they can (manufacturer captive-financing promotions). If they can't, decline the dealer financing and use your outside rate. The dealer will still sell you the car; their F&I office just doesn't make the finance spread.
▶Does trading in a car reduce the sales tax I pay?
In most states, yes — you pay sales tax only on the post-trade-in difference. In seven jurisdictions (California, Virginia, Maryland, Kentucky, Hawaii, D.C., and Michigan above the cap), sales tax applies to the full price regardless of trade-in. This calculator handles the distinction automatically based on your state selector. On a $40,000 car with an $8,000 trade-in at 7.25% tax, the difference-state bill is $2,320 and the full-price-state bill is $2,900 — a $580 gap on the same deal.
▶What's the 20/4/10 rule?
A conservative car-affordability framework: put at least 20% down, take a loan term no longer than 48 months, and keep total transportation costs (loan payment + insurance + fuel + maintenance) at or below 10% of gross monthly income. Popularized by Consumer Reports and Edmunds. At 2026 prices and rates, few new-car buyers hit all three gates, which is itself a signal — either cars have become too expensive relative to wages, buyers are overreaching, or both. The rule is conservative by design; use it as a ceiling check, not a hard requirement.
▶Should I buy new or used?
Used wins on total cost for most drivers — skipping year-one depreciation (15-20%) is free money. Used loses on APR (11.26% vs 6.37% prime-credit averages Q4 2025), reliability certainty, and sometimes feature availability. The sweet spot is typically a 2-4-year-old used car: the original owner ate the worst depreciation, the car has most of its useful life left, and certified pre-owned programs offer reasonable warranty coverage. If you're stretching to afford new, buying used two segments up often gets you a nicer car for less money.
▶Does my credit score affect my auto loan rate?
Dramatically. Q4 2025 Experian data: prime-credit (720+) borrowers average 6.37% new / 11.26% used. Near-prime (620-719) average about 9.5% new / 13.8% used. Sub-prime (580-619) average 15.7% new / 19.8% used. Deep sub-prime (below 580) can be 20%+. On a $25,000 60-month loan, the rate difference between prime and sub-prime is $9,000 in total interest. If your score is below 680, consider a 6-month credit rebuild (pay down revolving balances, dispute errors, avoid new inquiries) before applying — the rate improvement is usually worth the wait.
▶Can I refinance my auto loan?
Yes — works best when rates have dropped since you financed, your credit has improved significantly, or you're stuck in a dealer-markup rate from the original deal. Typical refinance break-even is 12-18 months: shop rates from your bank or credit union, compare to your current rate, and run the math. A 2-3% rate reduction on a $25,000 balance is roughly $1,500-$2,000 in total interest saved. Avoid refinancing when the new loan extends the term significantly — you can drop the monthly but add thousands in lifetime interest. We'll ship a dedicated auto-refinance calculator separately; for now, our generic refinance calculator covers the math for auto loans with similar accuracy.
▶What's a typical doc fee / title / registration cost?
Doc fees range $75 to $1,500 by state. California caps at $85. Florida has no cap and averages $600-$900 on new cars. Many states fall in the $200-$500 range. The calculator defaults to $600 as a reasonable national average; edit based on your specific dealer's quote. Title and registration vary: most states charge $30-$200 for title and $50-$250 annually for registration (some states, like California, have registration fees tied to vehicle value that can run into the hundreds). DMV and other filing fees typically add $25-$100. The defaults are conservative placeholders; your actual Out-the-Door quote from the dealer is the right source of truth.
▶Should I buy the extended warranty the dealer is offering?
Rarely. Extended service contracts sold at the F&I desk are typically priced at $2,000-$4,500 for a 3-7 year contract, with a 30-50% dealer markup over the wholesale cost. Rolling that $2,500 into your 60-month loan at 6.37% actually costs about $2,913. Most manufacturer-issued extended warranties are available directly from the manufacturer (or from online third parties like Endurance or CarShield) at 30-60% lower prices. Before agreeing at the F&I desk, request to see the wholesale price, ask whether the same coverage is available elsewhere, and consider whether you'd be better off putting that money in a repair savings account at a high-yield savings rate instead.
▶What about leases — when do they make sense?
Leases work for drivers who want a new car every 2-3 years, stay within a predictable mileage allowance (typically 10,000-15,000 miles/year), and don't care about building vehicle equity. Business owners with a legitimate business-use case can often deduct lease payments in ways that are harder with a purchased vehicle. Leases don't work well for high-mileage drivers (overage fees of $0.15-$0.25/mile add up fast), for people who keep cars 7+ years, or for anyone who wants the flexibility to modify, heavily customize, or sell on their own timeline. Enable the lease-vs-buy toggle in this tool to see both monthlies side by side for your specific vehicle.
Additional resources
- Experian — State of the Automotive Finance Market (quarterly) — Quarterly benchmark data on auto loan APRs by credit tier, for new and used vehicles. The authoritative source for 'is my quoted rate competitive' questions. Q4 2025 prime-credit averages: 6.37% new, 11.26% used.
- Edmunds Car Shopping Trends (quarterly) — Edmunds' quarterly industry reports include the source data on trade-in negative equity prevalence and average gap size — 31% underwater, $6,754 average (Q2 2025). Worth bookmarking for the most current numbers.
- JD Power Automotive OEM Intelligence — JD Power tracks auto-finance trend data, including the rise of 84-month loans from 7.3% of new-car sales in 2019 to 12.8% in March 2026. A primary source for 'how common is this' questions.
- FTC — Buying a New Car — Federal Trade Commission's consumer guide to new-car purchases, including advice on negotiating price, financing, and trade-ins. Plain language, no affiliate angle.
- Consumer Reports — Why an 84-Month Auto Loan Is a Bad Idea — CR's explainer on long-term auto loans with the lifetime-cost math laid out. Good reference for anyone being pitched a 72- or 84-month term at the F&I desk.
- Kelley Blue Book — Trade-In Value — Free vehicle valuation tool. Check your current car's trade-in value here before entering a number in this calculator's trade-in field — dealer first offers are often 10-20% below KBB.
- IRS Topic 510 — Business Use of Car — Relevant if you're buying a vehicle for business use. Covers the standard mileage rate vs actual expense method, depreciation rules, and record-keeping requirements.
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