This page converts centimeters of water into pounds per square inch using the factor 0.01422334331, 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. 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. Two tables follow: rounded steps for quick lookup, and a set of real reference quantities converted into pounds 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
0.0142233433071- The exact number of pounds per square inch in one centimeter of water
pounds per square inch- The converted result
How it works, step by step
- Enter the value in centimeters of water.
- It is multiplied by 0.0142233433071, the exact factor between the two units.
- The answer is shown in pounds per square inch, with the reverse conversion beneath it.
- Check the reference table if you want a figure of comparable size.
Worked examples
A car tyre: 2250 cmH₂O in pounds per square inch
A car tyre comes to about 2250 cmH₂O. Multiplying by the factor: 2250 × 0.0142233 = 32.0025 psi. Dividing the answer back by 0.0142233 returns the figure you started with, which is the quickest way to check you have the factor the right way up.
A steam boiler: 1.02e+04 cmH₂O in pounds per square inch
A steam boiler comes to about 1.02e+04 cmH₂O. Multiplying by the factor: 1.02e+04 × 0.0142233 = 145.078 psi. Dividing the answer back by 0.0142233 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 pounds per square inch are in one centimeter of water?
Exactly 0.0142233433071. 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 pounds per square inch?
pounds per square inch = centimeters of water × 0.0142233433071. Reversed, centimeters of water = pounds per square inch ÷ 0.0142233433071, which is the same as multiplying by 70.3069579639.
Which is the bigger unit, the centimeter of water or the pound per square inch?
The pound per square inch. One centimeter of water is only 0.0142233 of a pound per square inch, so it takes 70.307 centimeters of water to make one pound 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 pound per square inch?
The dominant US pressure unit for tyres, plumbing and compressors.
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 psi in my head?
Plenty of people do this in their head: divide by 70 instead of using the exact factor 0.01422334331. At 100 that shortcut gives 1.4285714 pounds per square inch, off by 0.006237 pounds 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 pounds per square inch reference tables
| Centimeters Of Water | Pounds Per Square Inch |
|---|---|
| 0.5 cmH₂O | 0.00711167 psi |
| 1 cmH₂O | 0.0142233 psi |
| 2 cmH₂O | 0.0284467 psi |
| 3 cmH₂O | 0.04267 psi |
| 5 cmH₂O | 0.0711167 psi |
| 10 cmH₂O | 0.142233 psi |
| 20 cmH₂O | 0.284467 psi |
| 25 cmH₂O | 0.355584 psi |
| 50 cmH₂O | 0.711167 psi |
| 75 cmH₂O | 1.06675 psi |
| 100 cmH₂O | 1.42233 psi |
| 250 cmH₂O | 3.55584 psi |
| 500 cmH₂O | 7.11167 psi |
| 1000 cmH₂O | 14.2233 psi |
| 5000 cmH₂O | 71.1167 psi |
Exact factor: 1 centimeter of water = 0.0142233433071 pounds per square inch.
| Quantity | cmH₂O | psi |
|---|---|---|
| Sea-level air | 1033 cmH₂O | 14.7 psi |
| A car tyre | 2250 cmH₂O | 32 psi |
| Blood pressure, systolic | 163.1 cmH₂O | 2.32 psi |
| A bicycle tyre | 6328 cmH₂O | 90 psi |
| A domestic water main | 4079 cmH₂O | 58.02 psi |
| A steam boiler | 1.02e+04 cmH₂O | 145 psi |
Published reference values, converted with the same factor this page uses.