Hydrostatic Pressure Calculator
Calculate pressure at a specified fluid depth using P = ρ g h.
Standard gravity: 9.80665 m/s² (32.174 ft/s²).
How to Use This Calculator
Select unit system
Choose SI or US customary units.
Enter fluid density
For water at ~20°C, use ≈ 1000 kg/m³ (or 1.94 slug/ft³).
Enter gravity and depth
Use standard gravity unless a different value is required; provide the depth below the free surface.
Calculate
Press Calculate to get pressure. Add atmospheric pressure if absolute pressure is required.
Formula
P = ρ · g · h
Where: P is hydrostatic pressure, ρ is fluid density, g is gravitational acceleration, h is depth.
Units: SI → Pa (N/m²). In US customary, result is in lb/ft².
Example: ρ = 1000 kg/m³, g = 9.81 m/s², h = 2 m ⇒ P = 19,620 Pa (≈ 19.6 kPa).
About Hydrostatic Pressure Calculator
Hydrostatic pressure increases linearly with depth in a static fluid. This calculator helps estimate gauge pressure at a given depth for engineering, oceanography, and process applications.
When to Use This Calculator
- Tank design: Determine wall loads.
- Submerged objects: Estimate pressure exposure.
- Hydraulics: Assess pressure in reservoirs and channels.
Why Use Our Calculator?
- ✅ Unit flexibility: SI and US customary.
- ✅ Clarity: Straightforward inputs with guidance.
- ✅ Accuracy: Uses the fundamental hydrostatic equation.
Frequently Asked Questions
Is depth measured from the free surface?
Yes. h is the vertical distance below the free surface. Pressure increases with depth.
Does fluid compressibility matter?
For liquids at moderate depths, compressibility is negligible. For gases or extreme depths, more complex models are required.
Gauge vs absolute pressure?
This formula yields gauge pressure. Add atmospheric pressure (~101.3 kPa) to obtain absolute pressure in air at sea level.