To convert millitorr to centimeters of water, multiply by 0.001359509806. 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. One thousandth of a torr, the working unit of vacuum deposition.
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. Below the calculator there is a step table for the values people look up most, and a second table putting real pressure figures into centimeters of water so the number you get has something to be compared against.
The formula
millitorr- The amount you are converting, in millitorr
0.00135950980632- The exact number of centimeters of water in one millitorr
centimeters of water- The converted result
How it works, step by step
- Enter the value in millitorr.
- It is multiplied by 0.00135950980632, 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
A domestic water main: 3e+06 mTorr in centimeters of water
At 3e+06 mTorr (a domestic water main), the same quantity in centimeters of water is 3e+06 × 0.00135951 = 4078.53 cmH₂O. One millitorr is 0.00135951 centimeters of water, so the numbers shrink as expected.
A car tyre: 1.65e+06 mTorr in centimeters of water
At 1.65e+06 mTorr (a car tyre), the same quantity in centimeters of water is 1.65e+06 × 0.00135951 = 2243.19 cmH₂O. One millitorr is 0.00135951 centimeters of water, so the numbers shrink as expected.
How to read your score
Frequently asked questions
How many centimeters of water are in one millitorr?
Exactly 0.00135950980632. 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 millitorr to centimeters of water?
centimeters of water = millitorr × 0.00135950980632. Reversed, millitorr = centimeters of water ÷ 0.00135950980632, which is the same as multiplying by 735.559240069.
Which is the bigger unit, the millitorr or the centimeter of water?
The centimeter of water. One millitorr is only 0.00135951 of a centimeter of water, so it takes 735.559 millitorr to make one centimeter 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 millitorr?
One thousandth of a torr, the working unit of vacuum deposition.
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 mTorr to cmH₂O in my head?
Plenty of people do this in their head: divide by 740 instead of using the exact factor 0.001359509806. At 100 that shortcut gives 0.13513514 centimeters of water, off by 0.0008158 centimeters of water or about 0.60%. Fine for a rough estimate, not fine for anything you are cutting to size or dosing.
Millitorr to centimeters of water reference tables
| Millitorr | Centimeters Of Water |
|---|---|
| 0.5 mTorr | 0.000679755 cmH₂O |
| 1 mTorr | 0.00135951 cmH₂O |
| 2 mTorr | 0.00271902 cmH₂O |
| 3 mTorr | 0.00407853 cmH₂O |
| 5 mTorr | 0.00679755 cmH₂O |
| 10 mTorr | 0.0135951 cmH₂O |
| 20 mTorr | 0.0271902 cmH₂O |
| 25 mTorr | 0.0339877 cmH₂O |
| 50 mTorr | 0.0679755 cmH₂O |
| 75 mTorr | 0.101963 cmH₂O |
| 100 mTorr | 0.135951 cmH₂O |
| 250 mTorr | 0.339877 cmH₂O |
| 500 mTorr | 0.679755 cmH₂O |
| 1000 mTorr | 1.35951 cmH₂O |
| 5000 mTorr | 6.79755 cmH₂O |
Exact factor: 1 millitorr = 0.00135950980632 centimeters of water.
| Quantity | mTorr | cmH₂O |
|---|---|---|
| Sea-level air | 7.6e+05 mTorr | 1033 cmH₂O |
| A car tyre | 1.655e+06 mTorr | 2250 cmH₂O |
| Blood pressure, systolic | 1.2e+05 mTorr | 163.1 cmH₂O |
| A bicycle tyre | 4.654e+06 mTorr | 6328 cmH₂O |
| A domestic water main | 3e+06 mTorr | 4079 cmH₂O |
| A steam boiler | 7.501e+06 mTorr | 1.02e+04 cmH₂O |
Published reference values, converted with the same factor this page uses.