Kilopascals to psi converter

How to convert kPa to psi

Multiply kilopascals by 0.145038: psi = kPa × 0.145038. So 220 kPa = 31.91 psi and 250 kPa = 36.26 psi. It applies to metric tire placards, equipment specs and weather pressures, and keeps the reference: a gauge reading in kPa becomes a gauge reading in psi.

Multiply by 0.145 for a quick answer

Multiplying by 0.145 is within 0.03%: 220 kPa × 0.145 = 31.9 psi. Dividing by 7 is easier but 1.5% low, giving 31.43 psi.

Where 0.145038 comes from

A psi is 6,894.757 Pa: one pound-force, 4.4482216152605 N, spread over one square inch, 0.0254² m². A kPa is 1,000 Pa, so 1 kPa = 1,000 ÷ 6,894.757 = 0.1450377 psi (NIST SP 811, Appendix B8). 100 kPa, one bar, is 14.504 psi.

kPa to psi chart

Specs for hydraulics and other high pressures may use megapascals: 1 MPa is 1,000 kPa, or 145.04 psi.

Weather and engine readings are absolute

Barometric pressure is absolute pressure, measured from a vacuum. Canadian weather reports give it in kPa, and 101.3 kPa is 14.69 psi absolute (psia). A tire gauge reads above that air pressure, so its 220 kPa is gauge pressure.

Engine MAP sensors also read absolute pressure. At the standard atmosphere of 101.325 kPa, a 200 kPa MAP reading is 98.675 kPa above the air outside, so a boost gauge would show 14.31 psi. The 200 kPa itself is 29.01 psia.

Common mistakes

• Multiplying by 6.895. That is the psi-to-kPa direction and turns 220 kPa into 1,517 psi. A psi is the larger unit, so the psi number is always the smaller one.
• Treating Pa as kPa. 220,000 Pa is 220 kPa, or 31.91 psi. Reading it as kPa makes the answer 1,000 times too high.
• Comparing absolute with gauge. A weather report's 101.3 kPa and a tire gauge's 0 can describe the same outside air.

Related converters

For the reverse, use psi to kPa. For bar, use bar to psi: 2.2 bar is 220 kPa and gives the same 31.91 psi. To see how air pressure falls with height, use the altitude and air pressure calculator.