Pressure-to-Depth and Depth-to-Pressure Calculator

By Rusty


This calculator determines the water depth to reach a given pressure or the pressure at a given depth. You can enter the depth or pressure input with most common units and it will be converted automatically. This calculator does not add air pressure at the surface – the results are relative to the surface pressure.

(success) Enter depth or pressure followed by unit. (e.g. "110 psi" or "450 ft")

Pressure and Depth Output:


Hydrostatic Water Pressure Formula

This calculator uses simple hydrostatic pressure equations. The pressure, \(P\) of a fluid at depth depends only on the density, \(\rho\), the acceleration of gravity, \(g\), and the depth or height of the fluid column, \(h\).

\[P = \rho g h \]

The calculator uses the following values for these parameters:

\(\rho_{fresh} = 997.0474 \: kg/m^3 \) (for freshwater)
\(\rho_{salt} = 1023.6 \: kg/m^3 \) (for saltwater)
\(g = 9.80665 \: m/s^2 \)

Learn More

For watertight enclosure design, please check out Under Pressure.

This calculator uses the js-quantities library by gentooboontoo for unit conversions.



Rusty is the founder and CEO of Blue Robotics. His background is in engineering but he likes to be involved in everything at Blue Robotics!