Convert kilopascals to psi

The formula

psi = kilopascals × 0.14503774

kilopascals to psi — quick reference

kPa on the placard, psi on the gauge in your hand

Japanese, Korean and Australian vehicles routinely print tyre pressures in kilopascals, with 220 kPa front and 240 rear a common pair. Most handheld gauges, forecourt air lines and compressor displays read psi, so the placard says 220 while the equipment counts to about 32. Neither figure is unusual; they are different units describing the same air.

Kilopascals have one convenient property: 100 kPa is exactly 1 bar, so a placard in kPa converts to bar by shifting the decimal point two places. That makes it the unit bridging the other two, and it is why some cars print all three — a European placard, a Japanese manual and an American gauge can all be describing the same 2.2 bar.

Gauge reference and temperature both move the reading

Tyre gauges measure above atmospheric pressure rather than absolute, which is why a flat tyre reads 0 kPa instead of the roughly 101 kPa of atmosphere surrounding it. Absolute figures do appear in engineering and weather contexts, so a kilopascal value taken from anywhere other than a tyre gauge may already include that hundred.

Temperature shifts the reading by roughly 10 kPa for every 10 degrees Celsius, in both directions. A tyre checked warm reads high and ends up under-inflated if adjusted down to target, while a cold snap drops pressures enough to trigger the monitoring warning on a car that was fine the week before. Check first thing, before driving more than a mile or two.

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