Pressure Converter
Convert kPa, bar, psi, atmospheres, millibars and mmHg — tyre pressures, weather charts, blood pressure and engineering specs. Results update as you type; exact factors shown.
One kilopascal is 0.145 pounds per square inch — see the exact factor, not a rounded rule of thumb.
How the pressure converter works
Pressures convert through the pascal (1 N/m²). One bar is exactly 100 kPa; a standard atmosphere is exactly 101.325 kPa; 1 psi is 6.894757 kPa (a pound-force on a square inch); 1 mmHg is 133.322 Pa by the conventional definition.
The UK is metric for most trade and science but keeps miles, pints, stone and mpg (with the imperial gallon) in daily life.
Common pressure conversions
| From | To | Units |
|---|---|---|
| 1 bar | 14.5038 psi | bar to pounds per square inch |
| 1 psi | 6.8948 kPa | pound per square inch to kilopascals |
| 1 atm | 101.325 kPa | standard atmosphere to kilopascals |
| 32 psi | 220.6322 kPa | pounds per square inch to kilopascals |
| 220 kPa | 31.9083 psi | kilopascals to pounds per square inch |
| 1,013.25 mbar | 29.9213 inHg | millibar (hectopascal) to inches of mercury |
| 120 mmHg | 15.9987 kPa | millimetre of mercurys to kilopascals |
| 1 MPa | 145.0377 psi | megapascal to pounds per square inch |
| 100 kPa | 1 bar | kilopascals to bars |
| 30 inHg | 1,015.9167 mbar | inches of mercury to millibar (hectopascal) |
Units in this converter and their exact factors
| Unit | Symbol | One unit in pascals |
|---|---|---|
| pascal | Pa | 1 pascal |
| kilopascal | kPa | 1,000 pascal |
| megapascal | MPa | 1,000,000 pascal |
| bar | bar | 100,000 pascal |
| millibar (hectopascal) | mbar | 100 pascal |
| standard atmosphere | atm | 101,325 pascal |
| pound per square inch | psi | 6,894.757293168 pascal |
| millimetre of mercury | mmHg | 133.322387415 pascal |
| inch of mercury | inHg | 3,386.389 pascal |
FAQFrequently asked questions about pressure conversion
What tyre pressure is 32 psi in kPa?
About 221 kPa, or 2.2 bar.
How many psi are in a bar?
14.504 psi. One bar is roughly one atmosphere (0.987 atm).
What is standard atmospheric pressure?
101.325 kPa = 1,013.25 mbar (hPa) = 29.92 inHg = 14.696 psi.
Why is blood pressure measured in mmHg?
Historically it was read from a mercury column. 120/80 mmHg is about 16.0/10.7 kPa.
Are hectopascals and millibars the same?
Yes — 1 hPa = 1 mbar = 100 Pa. Weather services use hPa; older charts use mbar.
Where these figures come from
- BIPM — The International System of Units (SI Brochure, 9th edition) — definitions of the base and derived units.
- NIST Special Publication 811 — Guide for the Use of the International System of Units — the exact conversion factors used here.
- National Physical Laboratory (NPL) — United Kingdom's national measurement authority.
Last checked: September 2026. Conversion factors are fixed by definition and do not change with tax years or regulations.