Pressure converter
Convert one pressure into 12 units including Pa, bar, atm, psi and mmHg
Pick the units at both ends to see the result. Tyre and cylinder readings are usually gauge pressure, so confirm which your figure is.
This affects display only. Conversion always uses full precision.
| Unit | Symbol | Result |
|---|---|---|
| Megapascal | MPa | |
| Kilopascal | kPa | |
| Hectopascal | hPa | |
| Pascal | Pa | |
| Bar | bar | |
| Millibar | mbar | |
| Standard atmosphere | atm | |
| Pound per square inch | psi | |
| Kilogram-force per square centimetre | kgf/cm² | |
| Millimetre of mercury | mmHg | |
| Inch of mercury | inHg | |
| Millimetre of water | mmH₂O |
Example
Input
1 atm
Example result
kPa 101.325 bar 1.01325 psi 14.6959487755 mmHg 759.999891726
One standard atmosphere is exactly 760 torr, but the conventional millimetre of mercury is defined slightly differently, so the result reads 759.9999 rather than a round 760.
Technical details & limits
Conversions run through the pascal. The standard atmosphere is its defined 101325 pascals, the millimetre of mercury uses the conventional 133.322387415 pascals, psi follows from the defined pound-force and square inch, and kgf/cm² is 98066.5 pascals.
About this tool
Enter a value and pick its unit to get every other pressure unit at once: the pascal and its multiples, bar and millibar, the standard atmosphere, pounds per square inch, kilogram-force per square centimetre, and the millimetre of mercury, inch of mercury and millimetre of water.
Use cases
- Convert tyre pressure from psi into bar or kPa.
- Compare hectopascals and millibars in weather data.
- Convert blood pressure in mmHg into kilopascals.
How to use
- Type a number. Decimals and scientific notation such as 1.5e3 are accepted.
- Pick the unit the value is in and the unit you want it in. The ⇄ button swaps the two.
- The summary line gives the target unit; the table below lists the remaining pressure units, including legacy engineering and medical notations.
- Adjust the significant digits for a shorter or longer number. The conversion itself always runs at full precision.
Notes
The page converts the number itself and does not distinguish absolute pressure from gauge pressure. Tyre and cylinder readings are usually gauge pressure, which differs from absolute by about one atmosphere, so confirm which one your figure is. Kilogram-force per square centimetre is a legacy engineering unit rather than an SI one.
FAQ
- How many pascals and kilopascals are in one standard atmosphere?
- 1 standard atmosphere equals 101325 pascals, or 101.325 kilopascals. This tool uses the defined standard-atmosphere value rather than a live atmospheric-pressure reading for a location. When comparing weather data or instrument measurements, check whether each value is absolute pressure or gauge pressure. Converting units alone does not remove that difference in reference, and a precise numeric conversion cannot make differently referenced readings directly comparable.
- How many kilopascals are in one bar?
- 1 bar equals 100000 pascals, or 100 kilopascals. A bar is close to a standard atmosphere but is not the same unit. Check the unit label and the equipment's own requirements when reading a pump or industrial gauge. Similar-looking values should not be treated as interchangeable, and converting the displayed units does not establish the correct operating pressure or the pressure reference used by a device.
- What conversion factor does the tool use for millimeters of mercury?
- This tool uses the conventional factor of 133.322387415 pascals for 1 millimeter of mercury. Kilopascals and pascals differ by a factor of 1000. The page converts pressure units without interpreting the significance of a measured reading. When comparing instruments, also verify calibration conditions and whether the pressure is absolute, gauge, or another referenced quantity, because unit conversion does not resolve differences in how the measurement was obtained.
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