To convert centimeters of water to megapascals, multiply by 9.80665e-05. 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 unit ventilator and CPAP pressures are set in. Used for material strength and hydraulic systems.
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 megapascals, 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
9.80665e-05- The exact number of megapascals in one centimeter of water
megapascals- The converted result
How it works, step by step
- Enter the value in centimeters of water.
- It is multiplied by 9.80665e-05, the exact factor between the two units.
- The answer is shown in megapascals, with the reverse conversion beneath it.
- Check the reference table if you want a figure of comparable size.
Worked examples
A bicycle tyre: 6330 cmH₂O in megapascals
At 6330 cmH₂O (a bicycle tyre), the same quantity in megapascals is 6330 × 9.80665e-05 = 0.620761 MPa. One centimeter of water is 9.80665e-05 megapascals, so the numbers shrink as expected.
A domestic water main: 4080 cmH₂O in megapascals
Take a domestic water main, roughly 4080 cmH₂O. The conversion is a single multiplication — 4080 × 9.80665e-05 — giving 0.400111 MPa. Because the relationship is proportional, doubling the input doubles the answer to 0.800223 MPa.
How to read your score
Frequently asked questions
How many megapascals are in one centimeter of water?
Exactly 9.80665e-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 megapascals?
megapascals = centimeters of water × 9.80665e-05. Reversed, centimeters of water = megapascals ÷ 9.80665e-05, which is the same as multiplying by 10,197.1621298.
Which is the bigger unit, the centimeter of water or the megapascal?
The megapascal. One centimeter of water is only 9.80665e-05 of a megapascal, so it takes 10,197.2 centimeters of water to make one megapascal.
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 megapascal?
Used for material strength and hydraulic systems.
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 MPa in my head?
Plenty of people do this in their head: divide by 10,000 instead of using the exact factor 0.000098. At 100 that shortcut gives 0.01 megapascals, off by 0.0001934 megapascals or about 1.97%. Fine for a rough estimate, not fine for anything you are cutting to size or dosing.
Centimeters Of Water to megapascals reference tables
| Centimeters Of Water | Megapascals |
|---|---|
| 0.5 cmH₂O | 4.90333e-05 MPa |
| 1 cmH₂O | 9.80665e-05 MPa |
| 2 cmH₂O | 0.000196133 MPa |
| 3 cmH₂O | 0.000294199 MPa |
| 5 cmH₂O | 0.000490332 MPa |
| 10 cmH₂O | 0.000980665 MPa |
| 20 cmH₂O | 0.00196133 MPa |
| 25 cmH₂O | 0.00245166 MPa |
| 50 cmH₂O | 0.00490333 MPa |
| 75 cmH₂O | 0.00735499 MPa |
| 100 cmH₂O | 0.00980665 MPa |
| 250 cmH₂O | 0.0245166 MPa |
| 500 cmH₂O | 0.0490333 MPa |
| 1000 cmH₂O | 0.0980665 MPa |
| 5000 cmH₂O | 0.490333 MPa |
Exact factor: 1 centimeter of water = 9.80665e-05 megapascals.
| Quantity | cmH₂O | MPa |
|---|---|---|
| Sea-level air | 1033 cmH₂O | 0.1013 MPa |
| A car tyre | 2250 cmH₂O | 0.2206 MPa |
| Blood pressure, systolic | 163.1 cmH₂O | 0.016 MPa |
| A bicycle tyre | 6328 cmH₂O | 0.6205 MPa |
| A domestic water main | 4079 cmH₂O | 0.4 MPa |
| A steam boiler | 1.02e+04 cmH₂O | 1 MPa |
Published reference values, converted with the same factor this page uses.