🌊 Water Pressure at Depth Calculator
Find out how much pressure water exerts at a given depth, based on the standard hydrostatic pressure formula used in physics and diving.
How water pressure at depth is calculated
This calculator uses the hydrostatic pressure formula, P = ρ × g × h, where ρ (rho) is the density of the fluid, g is the acceleration due to gravity (9.81 m/s²), and h is the depth below the surface. This gives the gauge pressure — the extra pressure caused by the water itself, not counting the air pressure already pushing down from above.
Freshwater vs. seawater
Seawater is slightly denser than freshwater because of dissolved salts, so it produces more pressure at the same depth. This calculator uses 1000 kg/m³ for freshwater and 1025 kg/m³ for seawater, which are the standard reference values used in physics and oceanography.
Gauge pressure vs. absolute pressure
The absolute pressure adds standard atmospheric pressure (1 atm, about 101.3 kPa) on top of the water’s gauge pressure, since anything submerged is also under the weight of the atmosphere above the water’s surface. Divers and engineers often need absolute pressure, while gauge pressure describes the pressure added purely by the water column.
This tool is for general educational and planning purposes — for diving, engineering, or safety-critical work, always consult certified references, equipment manuals, or a qualified professional.