Pressure Converter: Units, Formulas, and Examples
Convert pressure between pascals, bar, PSI, standard atmospheres, and Torr.
How to convert pressure
Converted value = input value × source factor ÷ target factor. Factors express each unit in pascals.
Keep the source and target definitions consistent, apply the conversion to the original value, and round the final answer to the precision needed for your calculation.
Understanding pressure units
Pressure is force divided by area. One pascal equals one newton per square meter. One bar is 100,000 pascals; one standard atmosphere is 101,325 pascals. Torr uses exactly 1/760 of a standard atmosphere.
| Unit | In Pa |
|---|---|
| Pascals (Pa) | 1 |
| Kilopascals (kPa) | 1,000 |
| Megapascals (MPa) | 1,000,000 |
| Bar (bar) | 100,000 |
| Millibar (mbar) | 100 |
| Hectopascals (hPa) | 100 |
| Pounds-force per square inch (psi) | 6,894.75729317 |
| Standard atmospheres (atm) | 101,325 |
| Torr (Torr) | 133.322368421 |
Worked pressure examples
1 bar is approximately 14.503773773 PSI. 1 atmosphere = 101.325 kPa = 760 Torr.
Frequently asked questions
Which definitions should I use?
Converting a unit does not change gauge pressure into absolute pressure. Both readings must use the same reference; changing the reference requires the local atmospheric pressure.
Why do displayed results sometimes differ slightly?
Intermediate arithmetic uses browser floating-point numbers. Display rounding and the precision of an original measurement can affect the last digits. The unit conversion does not improve the accuracy of a measured value.
Does converting back recover the original value?
Using the unrounded result normally recovers the original quantity within floating-point precision. Copying a rounded number can introduce a small difference.
How are the unit definitions documented?
For physical unit definitions and conversion factors, see the NIST conversion reference.