Kilopascals to psi
Convert kilopascals to psi. Divide by 6.894757, with tyre placard tables and the hPa / millibar equivalence for weather.
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The formula
psi = kPa ÷ 6.894757293A psi is exactly 6894.757293168 pascals, so this division is exact in one direction and rounded in the other. The multiplier is 0.1450377.
Quick reference
| kPa | psi | bar |
|---|---|---|
| 50 kPa | 7.25 psi | 0.5 bar |
| 100 kPa | 14.50 psi | 1.0 bar |
| 150 kPa | 21.76 psi | 1.5 bar |
| 200 kPa | 29.01 psi | 2.0 bar |
| 220 kPa | 31.91 psi | 2.2 bar |
| 250 kPa | 36.26 psi | 2.5 bar |
| 300 kPa | 43.51 psi | 3.0 bar |
| 500 kPa | 72.52 psi | 5.0 bar |
Kilopascals and bar are trivially related: divide kPa by 100 to get bar. The awkward conversion is only ever the one to psi.
Tyre placards
Australian, New Zealand and many Asian-market vehicles print tyre pressures in kPa. The same car sold in the US prints psi:
| kPa | psi | Typical for |
|---|---|---|
| 190 kPa | 27.6 psi | small car, front |
| 200 kPa | 29.0 psi | small car |
| 220 kPa | 31.9 psi | mid-size car |
| 240 kPa | 34.8 psi | SUV |
| 280 kPa | 40.6 psi | light van |
| 350 kPa | 50.8 psi | van, laden |
The manufacturer’s figures are round in whichever unit the placard was printed in, which is why a “220 kPa” car and a “32 psi” car are the same car.
Weather: hPa, mbar and kPa
Forecasts use hectopascals, which are a hundredth of a kilopascal and numerically identical to the old millibar:
1 hPa = 1 mbar = 0.1 kPa
1013.25 hPa = 101.325 kPa = 1 atmosphere| Weather | hPa | kPa | psi |
|---|---|---|---|
| Strong high | 1040 hPa | 104.0 | 15.08 |
| Standard atmosphere | 1013 hPa | 101.3 | 14.70 |
| Ordinary low | 990 hPa | 99.0 | 14.36 |
| Deep low | 960 hPa | 96.0 | 13.92 |
| Severe typhoon centre | 920 hPa | 92.0 | 13.34 |
The whole range of surface weather spans about 1.7 psi, which is why nobody reports weather in psi.
Medical and vacuum
| kPa | psi | mmHg | |
|---|---|---|---|
| Blood pressure, 120 systolic | 16.0 | 2.32 | 120 |
| Blood pressure, 80 diastolic | 10.7 | 1.55 | 80 |
| Rough vacuum | 0.1 | 0.0145 | 0.75 |
See mmHg to kPa.
Estimating in your head
Divide by 7. 220 ÷ 7 is 31.4 against a true 31.9 psi — about 1.5% low. Dividing by 6.9 gets it right and is barely harder.