By Zencalcy Editorial TeamLast reviewed About us
In a still fluid, pressure rises linearly with depth because each layer must support the weight of the fluid above it. The gauge pressure is ρgh; the absolute pressure adds whatever pressure acts on the surface, usually the atmosphere.
Pressure at depth in a liquid, gauge and absolute.
P = P₀ + ρ g h P_gauge = ρ g h
P₀ is the pressure at the surface, ρ the fluid density, g standard gravity and h the depth. The result assumes the fluid is static and incompressible, which is accurate for water at ordinary depths.
| Symbol | Meaning |
|---|---|
| P | Absolute pressure at depth, in pascals. |
| P₀ | Pressure at the fluid surface, in pascals. |
| ρ | Fluid density, in kg/m³. |
| h | Depth below the surface, in metres. |
Gauge pressure is 1,000 × 9.80665 × 10 = 98,067 Pa, about 0.968 atm. Adding surface pressure gives an absolute pressure of 199,392 Pa — roughly 2 atm, as any diver knows at 10 m.
Continue with the Pressure Calculator, Seesaw Balance Calculator, or the Torque Calculator — or browse more statics tools and all physics calculators.
No, only on depth and fluid density. A narrow pipe and a wide lake have the same pressure at the same depth, a result called the hydrostatic paradox.
Results are computed from the standard equations of classical mechanics. Unit conversions use the SI definitions published by NIST. Air resistance is ignored unless the calculator names a drag model.
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Content updated: September 2026