About the Pressure Converter
Pressure is measured in many units depending on where you are and what you are doing. Tyre gauges show psi in the US and bar or kPa in much of the world, weather forecasts use millibars or hectopascals, doctors use mmHg for blood pressure, and engineers work in pascals and megapascals. This converter takes a value in any one of eleven units and shows it in all the others at once, so there is no need to chain conversions. It is handy for tyre pressures, scuba and compressor settings, weather readings, vacuum levels and technical specifications.
Updated October 2026
How to use the Pressure Converter
- 1Type the pressure you have.
- 2Choose the unit it is in.
- 3Read the value in every other unit in the list.
- 4Use the summary line for the most common three: kPa, bar and psi.
- 5Copy the result to your notes.
Common conversions at a glance
- 1 bar = 100 kPa = 14.5038 psi = 0.98692 atm.
- 1 atm = 101.325 kPa = 1.01325 bar = 14.696 psi = 760 mmHg.
- 1 psi = 6.89476 kPa = 0.0689476 bar.
- 1 kgf/cm² = 98.0665 kPa = 0.980665 bar = 14.223 psi.
- 1 inHg = 3.38639 kPa = 33.8639 mbar.
Choosing the right unit
Use psi for tyres and air tools in the US and bar or kPa elsewhere. Use hPa or mbar for weather and altitude, mmHg for medical readings and MPa for hydraulics and materials. Mixing them up can have serious results with pressure vessels and scuba tanks, so double-check any value that matters for safety.
Round sensibly: a tyre gauge is rarely accurate to better than half a psi, so quoting six digits adds nothing.
A worked example: a bicycle tyre label says 80 to 130 psi, but your track pump shows bar. Converting gives 5.5 to 9.0 bar, so a 7 bar setting sits in the middle of the range. A car tyre sticker of 220 kPa converts to 2.2 bar or 31.9 psi. Weather pressure of 1,008 mbar converts to 29.77 inches of mercury, the value some weather apps and aircraft altimeters use. In each case the converter gives all the units together, so you can read whichever one your gauge uses.
Related converters
Try the Unit Converter for lengths, areas and volumes, the Temperature Converter for gases and weather, the Energy Converter and Power Converter for technical work, and the Torque Converter for wheel nuts and bolts. The Density Calculator is useful for liquids and gases.
Features
- Eleven pressure units
- All results at once, no chaining
- Accurate standard conversion factors
- Handles very large and very small values
- Clear label of each unit
- Free and runs in your browser
Frequently asked questions
How do I convert psi to bar?
Divide the pressure in psi by 14.5038. A tyre at 32 psi is about 2.21 bar. To go from bar to psi, multiply by 14.5038, so 2.5 bar is about 36.3 psi.
How many kPa are in a bar?
One bar is exactly 100 kilopascals, or 100,000 pascals. One standard atmosphere is slightly more, at 101.325 kPa, which is why bar and atm are close but not the same.
What is the difference between gauge and absolute pressure?
Gauge pressure is measured against the air around you, so an unfilled tyre reads zero. Absolute pressure is measured against a perfect vacuum and is about 101.3 kPa (14.7 psi) higher at sea level. Always check which one a specification means.
What is a millibar?
A millibar is one thousandth of a bar, and equals one hectopascal. Weather maps use it, with average sea-level pressure about 1,013 mbar. Pressures below 1,000 mbar often come with wet and windy weather.
What is mmHg used for?
Millimetres of mercury is the traditional unit for blood pressure, and it is also used for vacuum and some lab instruments. A normal systolic blood pressure of 120 mmHg is about 16 kPa. One mmHg is approximately one torr.
What tyre pressure should I use?
Use the value from your vehicle's door-jamb sticker or handbook, which you can convert to the unit your pump shows. Check pressures when the tyres are cold, because driving warms the air and raises the reading.