Hydrostatic Pressure Tool

Calculator Inputs

Large screens use 3 columns, medium screens use 2, and mobile uses 1.

Fluid Preset

Fluid Density

Density Unit

Reference Depth

Depth Unit

Gravity (m/s²)

Atmospheric Pressure

Atmospheric Pressure Unit

Reference Area

Area Unit

Graph Points

Reset

The force result assumes the entered reference area experiences the calculated pressure at the selected depth.

Example Data Table

Fluid	Density (kg/m³)	Depth (m)	Area (m²)	Gauge Pressure (kPa)	Absolute Pressure (kPa)	Force (kN)
Water	1000	2.0	0.50	19.6200	120.9450	9.8100
Seawater	1025	5.0	1.00	50.2763	151.6013	50.2763
Light Oil	850	3.0	0.80	25.0155	126.3405	20.0124
Mercury	13595	1.2	0.20	160.0523	261.3773	32.0105

The table uses standard gravity of 9.81 m/s² and atmospheric pressure of 101.325 kPa.

Formula Used

Gauge Hydrostatic Pressure

P = ρgh

Where P is gauge pressure, ρ is fluid density, g is gravity, and h is vertical depth below the free surface.

Absolute Pressure

P_abs = P + P_atm

Absolute pressure adds atmospheric pressure to the calculated gauge pressure.

Hydrostatic Force on the Entered Area

F = PA

This tool applies the calculated pressure at the reference depth across the entered area to estimate force.

Specific Weight and Pressure Gradient

γ = ρg

Specific weight is the pressure rise per meter of fluid depth in SI base units.

How to Use This Calculator

Choose a fluid preset or select custom to enter your own density.
Enter fluid density, reference depth, gravity, atmospheric pressure, and reference area.
Select the correct units for density, depth, pressure, and area.
Set graph points to control how many depth samples appear in the chart.
Click the calculate button to view results above the form.
Review gauge pressure, absolute pressure, force, head, and gradient values.
Use the CSV button to export tabular results.
Use the PDF button to create a compact summary document.

Frequently Asked Questions

1) What is hydrostatic pressure?

Hydrostatic pressure is the pressure created by a fluid at rest because of its weight. It increases with vertical depth, density, and gravitational acceleration.

2) Why does pressure increase with depth?

A deeper point supports a taller column of fluid above it. That larger fluid weight produces higher pressure at the deeper location.

3) What is the difference between gauge and absolute pressure?

Gauge pressure measures fluid pressure above surrounding atmospheric pressure. Absolute pressure includes atmospheric pressure, so it is always higher by that atmospheric amount.

4) Does container shape affect hydrostatic pressure?

For a static fluid, pressure at a point depends on density, gravity, and vertical depth. Container shape does not change pressure at the same depth.

5) Can I use this tool for planets other than Earth?

Yes. Enter a different gravity value to model pressure conditions on another planet, moon, or custom engineering environment.

6) When is the force formula F = PA appropriate?

It is appropriate when the entered area is treated as experiencing the calculated pressure uniformly at the selected reference depth. Large submerged surfaces with varying depth need distributed-force methods.

7) Which density unit should I choose?

Choose the unit that matches your source data. The tool converts kg/m³, g/cm³, and lb/ft³ internally before performing the calculations.

8) What does the graph represent?

The graph plots gauge pressure versus depth. It helps you see the linear relationship between depth and hydrostatic pressure for the selected fluid and gravity.