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 pound per square inch is 6.8948 kilopascals — 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 US uses customary units (US gallon, short ton, °F) in daily life; NIST SP 811 gives the exact SI factors.
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 | millimeter 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 |
| millimeter 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 Institute of Standards and Technology (NIST) — United States's national measurement authority.
Last checked: September 2026. Conversion factors are fixed by definition and do not change with tax years or regulations.