Hydrostatic Pressure Calculator
Hydrostatic pressure increases with fluid density, gravity and depth. This calculator reports gauge pressure and adds a supplied surface pressure to estimate absolute pressure.
How to use this calculator
- Enter fluid density, depth, gravity and the absolute pressure at the surface, using pascals for pressure values.
- Check the labels and units before applying the result to a real task.
- Change one input at a time when comparing scenarios.
Formula and method
Pgage = ρgh; Pabsolute = Psurface + ρgh
- Pgage = ρgh; Pabsolute = Psurface + ρgh
- The formula assumes a static fluid with approximately constant density. Flow speed, pressure loss and changing fluid composition are not included.
Worked examples
Worked example
At 10 m below water with density 1,000 kg/m³ and gravity 9.81 m/s².
Gauge pressure is 1,000×9.81×10 = 98,100 Pa; at 101,325 Pa surface pressure, absolute pressure is 199,425 Pa.
Gauge pressure is 1,000×9.81×10 = 98,100 Pa; at 101,325 Pa surface pressure, absolute pressure is 199,425 Pa.
Understanding the result
Hydrostatic pressure increases with fluid density, gravity and depth. This calculator reports gauge pressure and adds a supplied surface pressure to estimate absolute pressure.
The formula assumes a static fluid with approximately constant density. Flow speed, pressure loss and changing fluid composition are not included.
Important notes
The formula assumes a static fluid with approximately constant density. Flow speed, pressure loss and changing fluid composition are not included.
Displayed values are rounded for readability; retain appropriate precision when continuing a calculation.
Frequently asked questions
What is gauge pressure?
Gauge pressure is the amount above the local surface pressure. Absolute pressure includes both the surface reference pressure and the fluid-column pressure.
Why does density matter?
A denser fluid has more mass per unit volume, so the same depth produces a larger fluid-column pressure.
Can I use this for moving pipes?
It estimates static pressure with depth. Flowing systems need additional relationships for velocity, friction and local losses.
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Related explanations
Learn the method behind the number or compare the terminology before using the calculator.
This page provides a calculation tool plus explanatory information so you can understand what the result means and when the underlying method may not fit your situation.