This page converts centimeters of water into kilopounds per square inch using the factor 1.422334331e-05, and shows the reverse figure alongside it. Both units measure pressure, which is why one number does the whole job.
The unit ventilator and CPAP pressures are set in. One thousand psi; the unit US steel and alloy strengths are quoted 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 kilopounds per square inch, which is usually more useful than the bare number.
The formula
centimeters of water- The amount you are converting, in centimeters of water
1.42233433071e-05- The exact number of kilopounds per square inch in one centimeter of water
kilopounds per square inch- The converted result
How it works, step by step
- Enter the value in centimeters of water.
- It is multiplied by 1.42233433071e-05, 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 domestic water main: 4080 cmH₂O in kilopounds per square inch
At 4080 cmH₂O (a domestic water main), the same quantity in kilopounds per square inch is 4080 × 1.42233e-05 = 0.0580312 ksi. One centimeter of water is 1.42233e-05 kilopounds per square inch, so the numbers shrink as expected.
Sea-level air: 1030 cmH₂O in kilopounds per square inch
Sea-level air comes to about 1030 cmH₂O. Multiplying by the factor: 1030 × 1.42233e-05 = 0.01465 ksi. Dividing the answer back by 1.42233e-05 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 centimeter of water?
Exactly 1.42233433071e-05. 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 centimeters of water to kilopounds per square inch?
kilopounds per square inch = centimeters of water × 1.42233433071e-05. Reversed, centimeters of water = kilopounds per square inch ÷ 1.42233433071e-05, which is the same as multiplying by 70,306.9579639.
Which is the bigger unit, the centimeter of water or the kilopound per square inch?
The kilopound per square inch. One centimeter of water is only 1.42233e-05 of a kilopound per square inch, so it takes 70,307 centimeters of water 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 centimeter of water?
The unit ventilator and CPAP pressures are set in.
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.
Is there a quick way to do cmH₂O to ksi in my head?
Plenty of people do this in their head: divide by 70,000 instead of using the exact factor 0.000014. At 100 that shortcut gives 0.0014285714 kilopounds per square inch, off by 0.000006 kilopounds per square inch or about 0.44%. Fine for a rough estimate, not fine for anything you are cutting to size or dosing.
Centimeters Of Water to kilopounds per square inch reference tables
| Centimeters Of Water | Kilopounds Per Square Inch |
|---|---|
| 0.5 cmH₂O | 7.11167e-06 ksi |
| 1 cmH₂O | 1.42233e-05 ksi |
| 2 cmH₂O | 2.84467e-05 ksi |
| 3 cmH₂O | 4.267e-05 ksi |
| 5 cmH₂O | 7.11167e-05 ksi |
| 10 cmH₂O | 0.000142233 ksi |
| 20 cmH₂O | 0.000284467 ksi |
| 25 cmH₂O | 0.000355584 ksi |
| 50 cmH₂O | 0.000711167 ksi |
| 75 cmH₂O | 0.00106675 ksi |
| 100 cmH₂O | 0.00142233 ksi |
| 250 cmH₂O | 0.00355584 ksi |
| 500 cmH₂O | 0.00711167 ksi |
| 1000 cmH₂O | 0.0142233 ksi |
| 5000 cmH₂O | 0.0711167 ksi |
Exact factor: 1 centimeter of water = 1.42233433071e-05 kilopounds per square inch.
| Quantity | cmH₂O | ksi |
|---|---|---|
| Sea-level air | 1033 cmH₂O | 0.0147 ksi |
| A car tyre | 2250 cmH₂O | 0.032 ksi |
| Blood pressure, systolic | 163.1 cmH₂O | 0.00232 ksi |
| A bicycle tyre | 6328 cmH₂O | 0.09 ksi |
| A domestic water main | 4079 cmH₂O | 0.05802 ksi |
| A steam boiler | 1.02e+04 cmH₂O | 0.145 ksi |
Published reference values, converted with the same factor this page uses.