To convert pounds per square inch to kilopounds per square inch, multiply by 0.001. That factor is the whole relationship: both units measure pressure, so the conversion is a proportion with no offset and no substance-specific constant.
One thousand psi; the unit US steel and alloy strengths are quoted in. The dominant US pressure unit for tyres, plumbing and compressors.
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. Below the calculator there is a step table for the values people look up most, and a second table putting real pressure figures into kilopounds per square inch so the number you get has something to be compared against.
The formula
pounds per square inch- The amount you are converting, in pounds per square inch
0.001- The exact number of kilopounds per square inch in one pound per square inch
kilopounds per square inch- The converted result
How it works, step by step
- Enter the value in pounds per square inch.
- It is multiplied by 0.001, the exact factor between the two units.
- The answer is shown in kilopounds per square inch, with the reverse conversion beneath it.
- Check the reference table if you want a figure of comparable size.
Worked examples
A steam boiler: 145 psi in kilopounds per square inch
At 145 psi (a steam boiler), the same quantity in kilopounds per square inch is 145 × 0.001 = 0.145 ksi. One pound per square inch is 0.001 kilopounds per square inch, so the numbers shrink as expected.
A car tyre: 32 psi in kilopounds per square inch
A car tyre comes to about 32 psi. Multiplying by the factor: 32 × 0.001 = 0.032 ksi. Dividing the answer back by 0.001 returns the figure you started with, which is the quickest way to check you have the factor the right way up.
How to read your score
Frequently asked questions
How many kilopounds per square inch are in one pound per square inch?
Exactly 0.001. 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 inch to kilopounds per square inch?
kilopounds per square inch = pounds per square inch × 0.001. Reversed, pounds per square inch = kilopounds per square inch ÷ 0.001, which is the same as multiplying by 1000.
Which is the bigger unit, the pound per square inch or the kilopound per square inch?
The kilopound per square inch. One pound per square inch is only 0.001 of a kilopound per square inch, so it takes 1000 pounds per square inch to make one kilopound per square inch.
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 inch?
The dominant US pressure unit for tyres, plumbing and compressors.
What is a kilopound per square inch?
One thousand psi; the unit US steel and alloy strengths are quoted in.
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.
Pounds Per Square Inch to kilopounds per square inch reference tables
| Pounds Per Square Inch | Kilopounds Per Square Inch |
|---|---|
| 0.5 psi | 0.0005 ksi |
| 1 psi | 0.001 ksi |
| 2 psi | 0.002 ksi |
| 3 psi | 0.003 ksi |
| 5 psi | 0.005 ksi |
| 10 psi | 0.01 ksi |
| 20 psi | 0.02 ksi |
| 25 psi | 0.025 ksi |
| 50 psi | 0.05 ksi |
| 75 psi | 0.075 ksi |
| 100 psi | 0.1 ksi |
| 250 psi | 0.25 ksi |
| 500 psi | 0.5 ksi |
| 1000 psi | 1 ksi |
| 5000 psi | 5 ksi |
Exact factor: 1 pound per square inch = 0.001 kilopounds per square inch.
| Quantity | psi | ksi |
|---|---|---|
| Sea-level air | 14.7 psi | 0.0147 ksi |
| A car tyre | 32 psi | 0.032 ksi |
| Blood pressure, systolic | 2.32 psi | 0.00232 ksi |
| A bicycle tyre | 90 psi | 0.09 ksi |
| A domestic water main | 58.02 psi | 0.05802 ksi |
| A steam boiler | 145 psi | 0.145 ksi |
Published reference values, converted with the same factor this page uses.