To use the scuba diving water pressure calculator, simply select the units, type in the diving depth and optionally an elevation, and get the result.
How to read the results
Depending on the diving depth you entered, and the elevation you’re at (for altitude diving), you will receive different results in bar, psi, and kPa.
Switching from saltwater to freshwater will give you slightly lower pressures, as the density is smaller.
Atm measurements are more or less identical to bar.
How to determine the water pressure at depth
For quick calculations of the water pressure at depth, add 1 bar/atm per 10m / 33ft of water depth to the 1 bar/atm of atmospheric pressure. This means, that at 10m / 33ft depth, the water pressure is 2 atm, and at 30m/99ft around 4 atm. At altitude, subtract 0.1 bar/atm per 1,000m/3,300ft elevation.
If you follow this quick approach, you should get by just fine. For more accurate calculations, use the scuba diving water pressure calculator above.
Here are some examples for you to practice. You’ll find all measurements in metric and imperial units and for simplicity’s sake, we assume freshwater and saltwater to be identical in pressure and density.
| Depth | Elevation | Pressure |
|---|---|---|
| 0m / 0ft | Sea level (0m / 0ft) | 1bar / 1atm / 14.7psi |
| 0m / 0ft | 1,000m / 3,300ft | 0.9bar / 0.9atm / 27.8psi |
| 10m / 33ft | Sea level (0m / 0ft) | 2bar / 2atm / 29.3psi |
| 10m / 33ft | 2,500m / 8,250 | 1.75bar / 1.75atm / 25.63psi |
| 16m / 53ft | Sea level (0m / 0ft) | 2.6bar / 2.6atm / 38psi |
| 16m / 53ft | 3,000m / 9,900ft | 2.3bar / 2.3atm / 33.6psi |
| 20m / 66ft | Sea level (0m / 0ft) | 3bar / 3atm / 43.8psi |
| 20m / 66ft | 3,000m / 9,900ft | 2.7 bar / 2.7atm / 39.5psi |
| 35m / 116ft | Sea level (0m / 0ft) | 4.5bar / 4,5atm / 65.7psi |
| 35m / 116ft | 500m / 1650ft | 4.45bar / 4.45atm / 65psi |
As you can see, using metric measurements like bar and m is a lot more intuitive than imperial ones due to the decimal base (multiples of 10).
However, if you practice enough, you’ll be able to do the same in any units of measurement you choose.
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