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Hydrostatic Pressure Calculator

Calculate the fluid pressure at a given depth — gauge pressure and absolute pressure in kPa, atm, and psi.

Gauge pressure (from the fluid alone)
98.07 kPa
Absolute pressure (kPa)
199.39 kPa
Absolute pressure (atm)
1.968 atm
Absolute pressure (psi)
28.92 psi

How it works

Hydrostatic pressure is the pressure added by a column of fluid above a given point: P = ρ × g × h, where ρ is the fluid's density, g is gravitational acceleration (9.80665 m/s², standard gravity), and h is the depth. This 'gauge pressure' is the pressure due to the fluid alone, above whatever pressure already exists at the surface.

Absolute pressure adds standard atmospheric pressure at sea level (101,325 Pa, i.e. 1 atm) on top of the gauge pressure, since that's the pressure already pressing down on the fluid's surface before you go any deeper. Depth is converted to meters internally (1 m = 3.28084 ft) before the formula runs, so the metric/imperial toggle only affects the depth input — fluid density is left in the universally-used kg/m³ regardless of unit system, the same convention this site's Buoyancy Calculator uses.

Results are given in kilopascals (kPa), standard atmospheres (atm), and pounds per square inch (psi) so the numbers are useful whether you're thinking in diving terms, plumbing/engineering terms, or scientific units.

FAQ

Why does a diver's ears feel pressure so quickly, even at shallow depth?

Because water is roughly 800 times denser than air, so the same depth of water adds vastly more pressure than the same height of atmosphere — every 10m (about 33ft) of seawater adds roughly 1 atm of pressure, which this calculator's formula reproduces: 1025 kg/m³ × 9.80665 m/s² × 10 m ≈ 100,518 Pa, almost exactly 1 atm (101,325 Pa).

Does the shape or width of the container matter?

No — hydrostatic pressure at a given depth depends only on the fluid's density and how deep that point is below the surface, not on the container's shape, width, or total volume (this is sometimes called the 'hydrostatic paradox'). A narrow tube and a wide tank filled with the same fluid to the same height produce identical pressure at the bottom.

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