This page converts millibars into centimeters of water using the factor 1.019716213, 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 meteorologist’s unit — sea-level pressure averages 1013.25 mbar.
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 centimeters of water, which is usually more useful than the bare number.
The formula
millibars- The amount you are converting, in millibars
1.01971621298- The exact number of centimeters of water in one millibar
centimeters of water- The converted result
How it works, step by step
- Enter the value in millibars.
- It is multiplied by 1.01971621298, the exact factor between the two units.
- The answer is shown in centimeters of water, with the reverse conversion beneath it.
- Check the reference table if you want a figure of comparable size.
Worked examples
Blood pressure, systolic: 160 mbar in centimeters of water
At 160 mbar (blood pressure, systolic), the same quantity in centimeters of water is 160 × 1.01972 = 163.155 cmH₂O. One millibar is 1.01972 centimeters of water, so the numbers grow as expected.
A car tyre: 2210 mbar in centimeters of water
Take a car tyre, roughly 2210 mbar. The conversion is a single multiplication — 2210 × 1.01972 — giving 2253.57 cmH₂O. Because the relationship is proportional, doubling the input doubles the answer to 4507.15 cmH₂O.
How to read your score
Frequently asked questions
How many centimeters of water are in one millibar?
Exactly 1.01971621298. 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 millibars to centimeters of water?
centimeters of water = millibars × 1.01971621298. Reversed, millibars = centimeters of water ÷ 1.01971621298, which is the same as multiplying by 0.980665.
Which is the bigger unit, the millibar or the centimeter of water?
The millibar. One millibar equals 1.01972 centimeters of water.
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 millibar?
The meteorologist’s unit — sea-level pressure averages 1013.25 mbar.
What is a centimeter of water?
The unit ventilator and CPAP pressures are set 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 mbar to cmH₂O in my head?
Plenty of people do this in their head: multiply by 1 instead of using the exact factor 1.019716213. At 100 that shortcut gives 100 centimeters of water, off by 1.972 centimeters of water or about 1.93%. Fine for a rough estimate, not fine for anything you are cutting to size or dosing.
Millibars to centimeters of water reference tables
| Millibars | Centimeters Of Water |
|---|---|
| 0.5 mbar | 0.509858 cmH₂O |
| 1 mbar | 1.01972 cmH₂O |
| 2 mbar | 2.03943 cmH₂O |
| 3 mbar | 3.05915 cmH₂O |
| 5 mbar | 5.09858 cmH₂O |
| 10 mbar | 10.1972 cmH₂O |
| 20 mbar | 20.3943 cmH₂O |
| 25 mbar | 25.4929 cmH₂O |
| 50 mbar | 50.9858 cmH₂O |
| 75 mbar | 76.4787 cmH₂O |
| 100 mbar | 101.972 cmH₂O |
| 250 mbar | 254.929 cmH₂O |
| 500 mbar | 509.858 cmH₂O |
| 1000 mbar | 1019.72 cmH₂O |
| 5000 mbar | 5098.58 cmH₂O |
Exact factor: 1 millibar = 1.01971621298 centimeters of water.
| Quantity | mbar | cmH₂O |
|---|---|---|
| Sea-level air | 1013 mbar | 1033 cmH₂O |
| A car tyre | 2206 mbar | 2250 cmH₂O |
| Blood pressure, systolic | 160 mbar | 163.1 cmH₂O |
| A bicycle tyre | 6205 mbar | 6328 cmH₂O |
| A domestic water main | 4000 mbar | 4079 cmH₂O |
| A steam boiler | 1e+04 mbar | 1.02e+04 cmH₂O |
Published reference values, converted with the same factor this page uses.