Common pressure conversions
| From | To | Multiply by |
|---|---|---|
| bar | psi | 14.5038 |
| psi | bar | 0.0689476 |
| bar | kPa | 100 |
| atm | kPa | 101.325 |
| mmHg | kPa | 0.133322 |
Tyre pressure
Tyre pressure is shown in psi on most pumps in Pakistan and the US, and in bar or kPa in Europe. A typical car tyre pressure of 32 psi is about 2.2 bar or 220 kPa. Use the figure printed inside your car’s door or in the manual, not the maximum on the tyre wall.
Weather and blood pressure
Weather reports give air pressure in hectopascals (hPa), which are the same as millibars: normal sea-level pressure is about 1,013 mbar. Blood pressure is measured in millimetres of mercury (mmHg), so 120/80 means 120 mmHg and 80 mmHg.
Gauge and absolute pressure
A tyre gauge shows pressure above the surrounding air (gauge pressure). Science problems often need absolute pressure, which adds about 1 atm (101.325 kPa). The converter changes units only, so add the atmosphere yourself if your question needs absolute pressure.