Pressure Converter
ConvertersConvert pressure between PSI, Pascal, Bar, Atmosphere, Torr, mmHg, kPa, MPa, and other common pressure units instantly.. Free, private — all processing in your browser.
The Pressure Converter translates between all common pressure units: PSI (pounds per square inch, US/industrial), Pascal (Pa, SI unit), kilopascal (kPa) and megapascal (MPa) (engineering), bar (automotive, weather), atmosphere (atm, standard atmospheric), Torr and millimeters of mercury (mmHg, medical/vacuum), and pounds per square foot (psf). Enter a value in any unit and see all equivalents instantly.
Pressure is force per area. Different contexts use different units: tire pressure is PSI in the US, bar in Europe. Atmospheric pressure in weather is typically hectopascals (hPa, same as millibars). Medical blood pressure is mmHg. Industrial and scientific use Pascal or its multiples. This tool handles all of them.
Pressure Converter — key features
Many units supported
Pascal, kPa, MPa, PSI, bar, atm, mmHg, Torr, hPa, mbar, psf.
Instant conversion
Enter any value and all others update.
Absolute vs gauge
Optional mode for absolute or gauge pressure calculation.
Engineering notation
Displays large or small values in scientific notation for clarity.
Common use presets
Tire pressure, atmospheric, blood pressure, vacuum settings.
Unit tooltips
Hover over any unit for explanation of when it’s used.
Copy results
One-click copy for any unit value.
Client-side only
All conversion in your browser.
How to use the Pressure Converter
- 1
Select input unit
Choose the unit of your source value.
- 2
Enter value
Type the pressure value.
- 3
See all conversions
All common pressure units show equivalent values.
- 4
Adjust absolute/gauge if needed
Choose absolute or gauge pressure mode.
- 5
Copy the unit you need
One-click copy of any output.
Common use cases for the Pressure Converter
Automotive
- →Tire pressure: Convert between PSI (US manuals) and bar (European manuals) for tire pressure specs.
- →Turbo boost pressure: Convert boost pressure between PSI and bar.
- →Fuel rail pressure: Convert between PSI, bar, and MPa in automotive engineering.
Engineering
- →Hydraulic systems: Convert design pressures between units for international specifications.
- →Pneumatic tools: Match tool pressure requirements in local units.
- →Process engineering: Chemical and oil engineering uses mix of PSI, bar, and Pa depending on region.
Weather and science
- →Weather reports: Convert atmospheric pressure between hPa and inches of mercury for weather analysis.
- →Scuba diving: Convert depth pressure (bar) to PSI for US-made tanks and gauges.
- →Medical: Convert blood pressure readings (mmHg) for different contexts.
Pressure Converter — examples
Car tire
Common tire pressure.
32 PSI
220.6 kPa, 2.206 bar, 2.177 atm, 1654 mmHg
Atmospheric pressure
Standard conditions.
1 atm
101325 Pa, 101.325 kPa, 14.696 PSI, 1.01325 bar, 760 mmHg
Blood pressure
Medical measurement.
120 mmHg
16 kPa, 2.32 PSI, 0.16 bar, 160 mbar
Scuba tank
High pressure.
3000 PSI
20684 kPa, 20.68 MPa, 206.84 bar, 204 atm
Weather low
Low pressure system.
985 hPa
985 mbar, 98.5 kPa, 14.29 PSI, 0.972 atm
Technical details
Pressure units and conversion factors:
Pascal (Pa): SI unit. 1 Pa = 1 N/m² = 1 kg/(m·s²). Quite small — 1 atm = 101325 Pa. Engineering typically uses kPa (1000 Pa) or MPa (million Pa).
PSI (pounds per square inch): US/imperial. 1 PSI = 6894.757 Pa. Common for tire pressure (30-35 PSI), water pressure, industrial equipment.
Bar: metric non-SI. 1 bar = 100,000 Pa. Close to atmospheric pressure (1 atm = 1.01325 bar). Common in automotive (turbo boost pressure, tire pressure in Europe), brewing, and weather.
Atmosphere (atm): standard atmospheric pressure. 1 atm = 101325 Pa = 14.696 PSI = 1.01325 bar. Used as a reference pressure.
Torr and mmHg: 1 Torr = 1 mmHg = 133.322 Pa. Nearly identical. Used in medical (blood pressure 120/80 mmHg), vacuum technology, and scientific contexts.
Hectopascal (hPa) = millibar (mbar): 1 hPa = 1 mbar = 100 Pa. Atmospheric weather reports use hPa (1013 hPa = 1 atm).
Pounds per square foot (psf): 1 psf = 47.88 Pa. Rare, used in some structural engineering.
Common pressure values:
- Vacuum of space: ~0 Pa
- Human breathing pressure: ~100-150 mmHg blood pressure
- Tire pressure car: 30-35 PSI (2-2.4 bar)
- Bicycle tire: 60-120 PSI
- Scuba tank: 3000 PSI (207 bar)
- Atmospheric: 1 atm = 101325 Pa = 14.7 PSI = 1013 mbar
- Water pressure typical home: 40-80 PSI
- Hydraulic press: 10,000+ PSI
Absolute vs. gauge pressure:
- Absolute pressure: relative to perfect vacuum
- Gauge pressure: relative to atmospheric (local surrounding air)
- Difference: atmospheric pressure, approximately 14.7 PSI
When someone says \\\"tire pressure is 32 PSI\\\", they mean gauge pressure. Absolute would be 32 + 14.7 = 46.7 PSI.
The tool converts numerically; you must understand which type (absolute or gauge) your value represents.
Vacuum: negative gauge pressure (below atmospheric). Expressed as negative PSI, or as \\\"inches of mercury vacuum\\\". Often written as positive numbers with \\\"vacuum\\\" label.
Common problems and solutions
⚠Absolute vs gauge
When someone says \"tire pressure 32 PSI\", they mean gauge pressure (above atmospheric). Absolute is 32+14.7 = 46.7 PSI. Make sure conversion doesn’t add 14.7 if you want gauge-to-gauge.
⚠Torr vs mmHg confusion
They’re essentially the same (Torr defined as 1/760 of atm, mmHg is actual mercury column height). Tiny differences (0.0001%) don’t matter outside precision metrology.
⚠Vacuum expressed as negative
Vacuum below atmospheric is negative gauge pressure. Some tools show as negative PSI (-5 PSI); others as positive inches of mercury vacuum. Verify the convention of your source.
⚠Pa vs kPa vs MPa
Pascal is a tiny unit. Most engineering uses kPa (kilo) or MPa (mega). 100 kPa = 100,000 Pa = 0.1 MPa. Double-check unit prefix to avoid factor-of-1000 errors.
⚠Altitude affects pressure
Atmospheric pressure decreases with altitude. 1 atm is sea level; higher altitudes have less. For precision work, specify altitude or use standard atmosphere reference.
⚠Bar vs millibar
1 bar = 1000 mbar. Meteorologists use mbar (or hPa, equivalent); automotive and engineering use bar. Don’t confuse.
⚠PSI vs psia vs psig
PSI alone often means gauge. psia = absolute, psig = gauge. In technical contexts, use explicit suffix to avoid ambiguity.
Pressure Converter — comparisons and alternatives
Compared to unit conversion calculators, this tool is focused on pressure with all common variants. General converters may miss specialty units like psf or Torr.
Compared to lookup tables, this tool provides exact conversion for any value, not just round numbers. Tables are reference; this tool is calculator.
Compared to manual calculation with conversion factors, this tool is instant and handles all units at once.
Frequently asked questions about the Pressure Converter
▶How many PSI is 1 bar?
1 bar = 14.504 PSI. Approximately 14.5 PSI. Bar is close to 1 atmosphere (1 bar = 0.987 atm).
▶What’s the difference between absolute and gauge pressure?
Absolute pressure is measured from perfect vacuum. Gauge pressure is measured from atmospheric pressure at your location. Tire gauges show gauge pressure — 0 reading means atmospheric, not vacuum.
▶What unit is used for atmospheric pressure?
Weather reports typically use hectopascals (hPa) or millibars (mbar) — they’re equivalent. Standard atmospheric pressure is 1013 hPa. US may also use inches of mercury (inHg).
▶Why does tire pressure use PSI in US?
Historical convention. US uses imperial units; tire pressure gauges were made in PSI and never switched to metric. European manufacturers use bar. They’re roughly 1 bar ≈ 14.5 PSI.
▶What is Torr?
A unit nearly identical to mmHg (millimeters of mercury). 1 Torr = 1 mmHg. Used in vacuum technology and some scientific contexts. Blood pressure is always in mmHg.
▶How do I convert kPa to PSI?
Divide kPa by 6.895 to get PSI. 200 kPa = 29 PSI. Or multiply PSI by 6.895 to get kPa. Use this tool for exact conversion.
▶Is my data private?
Yes. All conversion runs in your browser.
▶Why are there so many units?
Historical and regional reasons. Different industries adopted different units: automotive (PSI/bar), medical (mmHg), weather (hPa), engineering (kPa/MPa), science (Pa). Converters like this one bridge them.
Additional resources
- Pressure on Wikipedia — Background on pressure and its units.
- SI unit Pascal — BIPM on Pascal as SI derived unit.
- NIST pressure conversions — US National Institute of Standards on weights and measures.
- Standard atmosphere — Wikipedia on the atmospheric pressure reference.
- Engineering pressure units — Engineering context for pressure units in various industries.
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