This page converts centimeters of water into kilopascals using the factor 0.0980665, 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 standard tyre-pressure unit in metric countries.
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. The tables underneath give both a plain step-by-step lookup and a list of real quantities expressed in kilopascals, so you can sanity-check whether your answer is a plausible size.
The formula
centimeters of water- The amount you are converting, in centimeters of water
0.0980665- The exact number of kilopascals in one centimeter of water
kilopascals- The converted result
How it works, step by step
- Enter the value in centimeters of water.
- It is multiplied by 0.0980665, 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 steam boiler: 1.02e+04 cmH₂O in kilopascals
A steam boiler comes to about 1.02e+04 cmH₂O. Multiplying by the factor: 1.02e+04 × 0.0980665 = 1000.28 kPa. Dividing the answer back by 0.0980665 returns the figure you started with, which is the quickest way to check you have the factor the right way up.
A car tyre: 2250 cmH₂O in kilopascals
Take a car tyre, roughly 2250 cmH₂O. The conversion is a single multiplication — 2250 × 0.0980665 — giving 220.65 kPa. Because the relationship is proportional, doubling the input doubles the answer to 441.299 kPa.
How to read your score
Frequently asked questions
How many kilopascals are in one centimeter of water?
Exactly 0.0980665. 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 kilopascals?
kilopascals = centimeters of water × 0.0980665. Reversed, centimeters of water = kilopascals ÷ 0.0980665, which is the same as multiplying by 10.1971621298.
Which is the bigger unit, the centimeter of water or the kilopascal?
The kilopascal. One centimeter of water is only 0.0980665 of a kilopascal, so it takes 10.1972 centimeters of water 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 centimeter of water?
The unit ventilator and CPAP pressures are set 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 cmH₂O to kPa in my head?
Plenty of people do this in their head: divide by 10 instead of using the exact factor 0.0980665. At 100 that shortcut gives 10 kilopascals, off by 0.1934 kilopascals or about 1.97%. Fine for a rough estimate, not fine for anything you are cutting to size or dosing.
Centimeters Of Water to kilopascals reference tables
| Centimeters Of Water | Kilopascals |
|---|---|
| 0.5 cmH₂O | 0.0490333 kPa |
| 1 cmH₂O | 0.0980665 kPa |
| 2 cmH₂O | 0.196133 kPa |
| 3 cmH₂O | 0.2942 kPa |
| 5 cmH₂O | 0.490333 kPa |
| 10 cmH₂O | 0.980665 kPa |
| 20 cmH₂O | 1.96133 kPa |
| 25 cmH₂O | 2.45166 kPa |
| 50 cmH₂O | 4.90332 kPa |
| 75 cmH₂O | 7.35499 kPa |
| 100 cmH₂O | 9.80665 kPa |
| 250 cmH₂O | 24.5166 kPa |
| 500 cmH₂O | 49.0333 kPa |
| 1000 cmH₂O | 98.0665 kPa |
| 5000 cmH₂O | 490.332 kPa |
Exact factor: 1 centimeter of water = 0.0980665 kilopascals.
| Quantity | cmH₂O | kPa |
|---|---|---|
| Sea-level air | 1033 cmH₂O | 101.3 kPa |
| A car tyre | 2250 cmH₂O | 220.6 kPa |
| Blood pressure, systolic | 163.1 cmH₂O | 16 kPa |
| A bicycle tyre | 6328 cmH₂O | 620.5 kPa |
| A domestic water main | 4079 cmH₂O | 400 kPa |
| A steam boiler | 1.02e+04 cmH₂O | 1000 kPa |
Published reference values, converted with the same factor this page uses.