PSI to kPa Converter

How to convert psi to kilopascals

A pascal is one newton per square meter, and a kilopascal is 1,000 of them. A psi is one pound-force (4.4482216 N, as the pounds to newtons converter shows) on one square inch. A square inch is exactly 0.0254 × 0.0254 = 0.00064516 m², so 1 psi = 4.4482216 ÷ 0.00064516 = 6,894.757 Pa, or 6.894757 kPa. Because the inch and the pound are both defined exactly in metric terms, this factor is exact to as many digits as you care to carry. Every other pressure unit, from bar to mmHg, is on the pressure converter.

The common slip is a factor of 1,000. Kilopascals, megapascals and pascals differ by thousands, so 3,000 psi of concrete strength is about 20,684 kPa, which engineers write as 20.7 MPa. Bar sits in between: 100 kPa = 1 bar, so the psi to bar converter gives the same answer divided by 100.

Step by step

1. Take the pressure in psi.
2. Multiply it by 6.89476.
3. Round to one decimal (tires) or divide by 1,000 more for MPa.
4. If you need absolute pressure, add 101.325 kPa after converting.

See it on a scale

What are psi and kPa, and who uses each?

Psi is the US customary unit of pressure, used on American tire gauges, compressors and plumbing, while the kilopascal is the SI unit of choice for moderate pressures, used on Canadian and Australian tire placards, HVAC charts and building codes. In the US, household water typically runs 40 to 80 psi, and hydraulics and material strength specs are quoted in psi as well. Refrigeration charts, soil mechanics and weather science outside the US work in kPa.

Standard atmospheric pressure is 101.325 kPa, or 14.696 psi, which gives a handy anchor: about 100 kPa is one atmosphere, and about 7 kPa is one psi. Most pressure gauges sold in North America are dual-scale for exactly this reason.

Where megapascals take over

For high pressures and material strengths, kPa numbers get unwieldy, so engineers switch to MPa (1,000 kPa). Steel yield strengths, hydraulic system ratings and concrete grades are nearly always in MPa in metric documents.

What mistakes should you avoid when converting psi to kPa?

Avoid four slips: rounding the factor to 7, confusing kPa with MPa, reading hectopascals as kilopascals and mixing gauge with absolute pressure.

• Rounding the factor to 7. Multiplying by 7 instead of 6.895 adds 1.5%, so 35 psi becomes 245 kPa instead of 241.3 kPa.
• Confusing kPa and MPa. A 30 MPa concrete mix is 30,000 kPa, not 30 kPa. Check the prefix before you convert.
• Using hPa by mistake. Weather apps show hectopascals; 1,013 hPa is 101.3 kPa.
• Mixing gauge and absolute. A 10 psi boost is 68.9 kPa gauge but about 170.3 kPa absolute at sea level. Tuning tables usually want the absolute figure.

For quick estimates, multiply psi by 7 and subtract 1.5%. The bar to psi converter covers European specs, and the pressure converter shows every unit at once.