Pressure Calculator

Pascal (Pa) is the SI unit: 1 N/m². Other units include kilopascal (kPa = 1,000 Pa), bar (100,000 Pa), PSI (pounds per square inch, 6,895 Pa), atmosphere (atm = 101,325 Pa), and mmHg (Torr = 133.3 Pa). Atmospheric pressure at sea level is 101,325 Pa ≈ 1 atm ≈ 14.7 PSI.

Pascal's law states that pressure in an enclosed fluid transmits equally in all directions. A small force on a small piston creates pressure P = F₁/A₁. This same pressure on a larger piston produces force F₂ = P × A₂, where A₂ >> A₁. Car brakes, hydraulic lifts, and excavators use this principle.

Water above exerts weight, and pressure = weight/area = ρgh, where ρ is fluid density, g is gravity, and h is depth. For every 10 m of water depth, pressure increases by approximately 1 atm. At 10 m depth, pressure is 2 atm; at 100 m, about 11 atm. This is why deep-sea equipment needs thick pressure hulls.