One centimeter of water is exactly 0.03280839917 feet of water, so converting centimeters of water to feet of water is a single multiplication. Enter any figure and the result appears as you type — the arithmetic runs in your browser, so nothing is sent anywhere.
The unit ventilator and CPAP pressures are set in. Pump head expressed as a column of water — the way pump curves are drawn.
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 feet of water so the number you get has something to be compared against.
The formula
centimeters of water- The amount you are converting, in centimeters of water
0.0328083991697- The exact number of feet of water in one centimeter of water
feet of water- The converted result
How it works, step by step
- Enter the value in centimeters of water.
- It is multiplied by 0.0328083991697, the exact factor between the two units.
- The answer is shown in feet of water, 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 feet of water
A car tyre comes to about 2250 cmH₂O. Multiplying by the factor: 2250 × 0.0328084 = 73.8189 ftH₂O. Dividing the answer back by 0.0328084 returns the figure you started with, which is the quickest way to check you have the factor the right way up.
Sea-level air: 1030 cmH₂O in feet of water
At 1030 cmH₂O (sea-level air), the same quantity in feet of water is 1030 × 0.0328084 = 33.7927 ftH₂O. One centimeter of water is 0.0328084 feet of water, so the numbers shrink as expected.
How to read your score
Frequently asked questions
How many feet of water are in one centimeter of water?
Exactly 0.0328083991697. 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 feet of water?
feet of water = centimeters of water × 0.0328083991697. Reversed, centimeters of water = feet of water ÷ 0.0328083991697, which is the same as multiplying by 30.4799997961.
Which is the bigger unit, the centimeter of water or the foot of water?
The foot of water. One centimeter of water is only 0.0328084 of a foot of water, so it takes 30.48 centimeters of water to make one foot 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 centimeter of water?
The unit ventilator and CPAP pressures are set in.
What is a foot of water?
Pump head expressed as a column of water — the way pump curves are drawn.
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 ftH₂O in my head?
Plenty of people do this in their head: divide by 30 instead of using the exact factor 0.03280839917. At 100 that shortcut gives 3.3333333 feet of water, off by 0.05249 feet of water or about 1.60%. Fine for a rough estimate, not fine for anything you are cutting to size or dosing.
Centimeters Of Water to feet of water reference tables
| Centimeters Of Water | Feet Of Water |
|---|---|
| 0.5 cmH₂O | 0.0164042 ftH₂O |
| 1 cmH₂O | 0.0328084 ftH₂O |
| 2 cmH₂O | 0.0656168 ftH₂O |
| 3 cmH₂O | 0.0984252 ftH₂O |
| 5 cmH₂O | 0.164042 ftH₂O |
| 10 cmH₂O | 0.328084 ftH₂O |
| 20 cmH₂O | 0.656168 ftH₂O |
| 25 cmH₂O | 0.82021 ftH₂O |
| 50 cmH₂O | 1.64042 ftH₂O |
| 75 cmH₂O | 2.46063 ftH₂O |
| 100 cmH₂O | 3.28084 ftH₂O |
| 250 cmH₂O | 8.2021 ftH₂O |
| 500 cmH₂O | 16.4042 ftH₂O |
| 1000 cmH₂O | 32.8084 ftH₂O |
| 5000 cmH₂O | 164.042 ftH₂O |
Exact factor: 1 centimeter of water = 0.0328083991697 feet of water.
| Quantity | cmH₂O | ftH₂O |
|---|---|---|
| Sea-level air | 1033 cmH₂O | 33.9 ftH₂O |
| A car tyre | 2250 cmH₂O | 73.81 ftH₂O |
| Blood pressure, systolic | 163.1 cmH₂O | 5.352 ftH₂O |
| A bicycle tyre | 6328 cmH₂O | 207.6 ftH₂O |
| A domestic water main | 4079 cmH₂O | 133.8 ftH₂O |
| A steam boiler | 1.02e+04 cmH₂O | 334.6 ftH₂O |
Published reference values, converted with the same factor this page uses.