Hydrostatic Pressure Calculator Formula
Understand the math behind the hydrostatic pressure calculator. Each variable explained with a worked example.
Formulas Used
Gauge Pressure
gauge_p = density * 9.81 * depth / 1000Absolute Pressure
absolute_p = atm_pressure + density * 9.81 * depth / 1000Variables
| Variable | Description | Default |
|---|---|---|
density | Fluid Density (rho)(kg/m^3) | 1000 |
depth | Depth Below Surface (h)(m) | 10 |
atm_pressure | Atmospheric Pressure(kPa) | 101.325 |
How It Works
Hydrostatic Pressure
Pressure in a static fluid increases linearly with depth due to the weight of the fluid above.
Formula
P_gauge = rho g h
P_absolute = P_atm + rho g h
where rho is fluid density, g = 9.81 m/s^2, and h is the depth below the free surface. For water, pressure increases by approximately 9.81 kPa (about 1 atmosphere per 10.33 m) for each metre of depth.
Worked Example
10 m below the surface of fresh water at standard atmospheric pressure.
density = 1000depth = 10atm_pressure = 101.325
- 01Gauge pressure = 1000 x 9.81 x 10 = 98,100 Pa = 98.10 kPa
- 02Absolute pressure = 101.325 + 98.10 = 199.43 kPa
- 03This is approximately 2 atmospheres absolute.
Ready to run the numbers?
Open Hydrostatic Pressure Calculator