Hydrostatic Pressure Calculator

Calculate the pressure added by a stationary liquid column at depth. Compare gauge and absolute pressure with explicit unit handling.

How It Works

Formula

P_g = \rho g h

P_{abs} = P_{atm} + P_g

Variables, symbols and units

$P_g$: Gauge pressure added by the liquid column(Pa)
$P_{abs}$: Absolute pressure at depth(Pa)
$P_{atm}$: Atmospheric pressure reference(Pa)
$\rho$: Liquid density(kg/m³)
$g$: Gravity assumption(m/s²)
$h$: Liquid depth below the free surface(m)

Calculation method explained

Enter liquid depth and liquid density, then choose the pressure unit you care about. The calculator multiplies density, gravity, and depth to produce gauge pressure, and it adds atmospheric pressure only when you explicitly choose an absolute-pressure reference.

The calculator normalizes every input path to SI first: depth to metres, density to kilograms per cubic metre, gravity to metres per second squared, and atmospheric pressure to pascals. It then computes $P_g = \rho g h$ . If you enable an atmospheric-pressure reference, it also computes $P_{abs} = P_{atm} + P_g$ . The result is converted back to your selected output unit for the final display.

Frequently Asked Questions

What is the difference between gauge pressure and absolute pressure?

Gauge pressure is the pressure added by the liquid column alone. Absolute pressure adds a reference atmospheric pressure on top of that gauge pressure.

What density should I enter?

Enter the actual density of the liquid in your setup. Water, saltwater, oils, and process fluids can differ enough to move the result materially.

Why can the same depth produce different answers?

Hydrostatic pressure depends on depth, liquid density, gravity, and whether you are reading gauge or absolute pressure. Change any of those and the answer changes.

Does this cover flowing liquids or pump losses?

No. This calculator is only for static liquid columns. It does not model flow, friction loss, Bernoulli effects, pump sizing, vapor pressure, or structural checks.