About this tool
Hydrostatic Pressure & Pascal Calculator is a free, in-browser tool with two modes. 'Pressure at depth' finds the pressure a column of fluid exerts; 'Hydraulic (Pascal)' finds the force a hydraulic press multiplies through two pistons. Pick a fluid preset or enter any density — all math runs locally and nothing is uploaded.
At depth the gauge pressure is P = ρ·g·h, where ρ is fluid density, g is 9.81 m/s² and h is depth; the absolute pressure adds atmospheric pressure P₀ (default 101325 Pa). Results are shown in pascals, kilopascals, psi and atmospheres. In hydraulic mode, Pascal's law says pressure is equal throughout, so a force on the small piston becomes F₂ = F₁·(A₂ ÷ A₁) on the large one. Piston areas come from their diameters as A = π·d² ÷ 4, and the mechanical advantage is the area ratio A₂ ÷ A₁.
Use depth mode for diving, tank or dam calculations, and hydraulic mode to size a jack, brake or press. Every field is live, so you can see how doubling a piston diameter quadruples the output force.