What this calculator does
Turn a pressure in kilopascals (kPa) into pounds per square inch (psi), or back again. The kilopascal is the metric pressure unit. You'll see it on tire placards in Canada, Australia and many other countries, in weather reports (often as hectopascals) and in engineering specs. PSI is the US unit found on American gauges, air compressors and owner's manuals. Cars sold in several countries often list both on the sticker on the door frame (door jamb). But older manuals and imported equipment may give only one.
One pascal is one newton (a unit of force) per square meter, so a kilopascal is 1,000 N/m². One psi is about 6.894757 kPa. That means one kilopascal is about 0.145038 psi.
Where it's used
Why this math matters outside the classroom:
- Tire placards. A door placard listing 240 kPa calls for about 35 psi.
- Air pressure. Standard sea-level pressure of 101.325 kPa is about 14.696 psi.
- Bike tires. A road bike tire marked 100 psi is at about 690 kPa.
- Espresso machines. A machine brewing at 900 kPa (9 bar) works at about 130.5 psi.
- Hydraulics. Engineers convert a 20 MPa hydraulic spec to about 2,900 psi.
Grade level and standards: Grades 6–7; Common Core State Standards for Mathematics 6.RP.A.3.d. © Copyright 2010. National Governors Association Center for Best Practices and Council of Chief State School Officers. All rights reserved.
How to use it
- Enter a pressure in kPa or psi.
- Choose kPa to psi, or psi to kPa.
- Read the result and the working. The table lists common tire and air-pressure values for the direction you chose.
What the inputs mean
- Value to convert
- A pressure in kilopascals (for kPa → psi) or psi (for psi → kPa). If your number is a gauge reading, keep it as a gauge reading.
- Direction
- Which way to convert.
Formula and method
psi = kPa × 1,000 ÷ 6,894.757293168 ≈ kPa × 0.14503773773 kPa = psi × 6.894757293168
The psi is defined from the pound, standard gravity and the inch. So its size in pascals (Pa) is a long decimal: 6,894.757293168… Pa. Neither direction has a short, exact factor. The calculator keeps full precision and shows 12 significant figures, counting only the meaningful digits.
Both scales start at the same place: zero kPa and zero psi are the same pressure. So there's nothing to add or subtract, only a single multiplication.
Worked example
A placard lists 220 kPa. What is that in psi?
- The conversion factor, to 12 significant figures: 1 kPa ≈ 0.14503773773 psi.
- 220 × 0.14503773773 = 31.9083023006.
Result: 220 kPa is about 31.9 psi, so a gauge in psi should read 32.
Understanding the result
Here's a handy shortcut you can do in your head: multiply kPa by 0.145, or divide by 7 for a rougher figure. 220 kPa × 0.145 = 31.9 psi, within 0.03% of exact. 220 ÷ 7 = 31.4 psi, about 1.5% low. For psi to kPa, multiply by 6.9, which comes out about 0.08% high.
Normal air pressure at sea level is 101.325 kPa, which is 14.6959 psi. Weather maps usually show the same pressure as 1,013.25 hPa (hectopascals), and 1 hPa is 0.1 kPa.
Watch out for this one: tire placards give gauge pressure, the amount above the surrounding air. Scientific and weather values are absolute, measured from zero. About 101 kPa (14.7 psi) separates the two. This converter doesn't add or remove it for you.
Assumptions and limitations
- psi means pound-force per square inch under standard gravity.
- Both values are the same kind of pressure, either gauge or absolute.
- It doesn't convert between gauge and absolute pressure.
- Cheap gauges are often accurate only to within a few kPa. So extra decimals in the result don't add any real precision.
Frequently asked questions
How many kPa is 1 psi?
About 6.89475729317 kPa.
What is 250 kPa in psi?
About 36.26 psi.
Is kPa the same as kN/m²?
Yes. A pascal is one newton per square meter, so a kilopascal is one kilonewton per square meter.
Why does my tire placard show kPa and psi values that don't match exactly?
Manufacturers round each unit to a convenient number, such as 240 kPa and 35 psi. 240 kPa is 34.81 psi, so the printed pair is a rounded match, not an exact conversion.
How this calculator is checked
Method: 1 kPa = 1,000 N/m²; 1 psi = 0.45359237 kg × 9.80665 m/s² ÷ (0.0254 m)² = 6,894.757293168… Pa. The calculation is covered by automated tests with known reference values and edge cases. Last updated 2026-10-18. Found a problem? Tell us.
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