To convert pounds per square foot to kilopascals, multiply by 0.04788025898. That factor is the whole relationship: both units measure pressure, so the conversion is a proportion with no offset and no substance-specific constant.
The standard tyre-pressure unit in metric countries. The unit US building codes give floor, roof and wind loads in.
Gauge versus absolute. A tyre gauge reading 32 psi means 32 psi above atmospheric, which is about 46.7 psi absolute. Converting the number is straightforward; remembering which zero it was measured from is where the mistakes happen. N/mm² and MPa are the same size, so a drawing quoting either is quoting the same stress. Two tables follow: rounded steps for quick lookup, and a set of real reference quantities converted into kilopascals, which is usually more useful than the bare number.
The formula
pounds per square foot- The amount you are converting, in pounds per square foot
0.0478802589803- The exact number of kilopascals in one pound per square foot
kilopascals- The converted result
How it works, step by step
- Enter the value in pounds per square foot.
- It is multiplied by 0.0478802589803, the exact factor between the two units.
- The answer is shown in kilopascals, with the reverse conversion beneath it.
- Check the reference table if you want a figure of comparable size.
Worked examples
A bicycle tyre: 1.3e+04 psf in kilopascals
At 1.3e+04 psf (a bicycle tyre), the same quantity in kilopascals is 1.3e+04 × 0.0478803 = 622.443 kPa. One pound per square foot is 0.0478803 kilopascals, so the numbers shrink as expected.
A steam boiler: 2.09e+04 psf in kilopascals
At 2.09e+04 psf (a steam boiler), the same quantity in kilopascals is 2.09e+04 × 0.0478803 = 1000.7 kPa. One pound per square foot is 0.0478803 kilopascals, so the numbers shrink as expected.
How to read your score
Frequently asked questions
How many kilopascals are in one pound per square foot?
Exactly 0.0478802589803. Every figure on this page is that one number multiplied by your input, so the only rounding is at the display step.
What is the formula to convert pounds per square foot to kilopascals?
kilopascals = pounds per square foot × 0.0478802589803. Reversed, pounds per square foot = kilopascals ÷ 0.0478802589803, which is the same as multiplying by 20.8854342332.
Which is the bigger unit, the pound per square foot or the kilopascal?
The kilopascal. One pound per square foot is only 0.0478803 of a kilopascal, so it takes 20.8854 pounds per square foot to make one kilopascal.
What does this quantity actually measure?
Both units measure pressure. That is why a single factor is enough: there is no temperature offset and no material property involved, unlike conversions that cross between different quantities.
What is a pound per square foot?
The unit US building codes give floor, roof and wind loads in.
What is a kilopascal?
The standard tyre-pressure unit in metric countries.
Why does my answer differ from another converter?
Almost always because the other tool rounded the factor before multiplying. This page keeps full double precision through the calculation and rounds only for display, and it prints the factor it used so you can see where any difference came from.
Is there a quick way to do psf to kPa in my head?
Plenty of people do this in their head: divide by 21 instead of using the exact factor 0.04788025898. At 100 that shortcut gives 4.7619048 kilopascals, off by 0.02612 kilopascals or about 0.55%. Fine for a rough estimate, not fine for anything you are cutting to size or dosing.
Pounds Per Square Foot to kilopascals reference tables
| Pounds Per Square Foot | Kilopascals |
|---|---|
| 0.5 psf | 0.0239401 kPa |
| 1 psf | 0.0478803 kPa |
| 2 psf | 0.0957605 kPa |
| 3 psf | 0.143641 kPa |
| 5 psf | 0.239401 kPa |
| 10 psf | 0.478803 kPa |
| 20 psf | 0.957605 kPa |
| 25 psf | 1.19701 kPa |
| 50 psf | 2.39401 kPa |
| 75 psf | 3.59102 kPa |
| 100 psf | 4.78803 kPa |
| 250 psf | 11.9701 kPa |
| 500 psf | 23.9401 kPa |
| 1000 psf | 47.8803 kPa |
| 5000 psf | 239.401 kPa |
Exact factor: 1 pound per square foot = 0.0478802589803 kilopascals.
| Quantity | psf | kPa |
|---|---|---|
| Sea-level air | 2116 psf | 101.3 kPa |
| A car tyre | 4608 psf | 220.6 kPa |
| Blood pressure, systolic | 334.1 psf | 16 kPa |
| A bicycle tyre | 1.296e+04 psf | 620.5 kPa |
| A domestic water main | 8354 psf | 400 kPa |
| A steam boiler | 2.089e+04 psf | 1000 kPa |
Published reference values, converted with the same factor this page uses.