Pressure Calculator

Pressure is force spread over an area — the reason sharp knives cut (tiny area, huge pressure from modest force) and deep-sea submersibles need thick hulls (water pressure rises with depth). Scuba divers, tire gauges, weather maps, and hydraulic presses all speak the language of pascals, bar, psi, or atmospheres. One pascal equals one newton per square meter.

Pressure definitions:

P = F / A (direct pressure from force and area)

P = ρ × g × h (hydrostatic pressure in a fluid column)

Where P is pressure, F is normal force, A is area, ρ is fluid density, g is gravity, and h is depth below the free surface. Gauge pressure measures relative to atmospheric; absolute pressure adds ambient ~101.3 kPa at sea level.

Enter force and area for contact pressure, or fluid density and depth for underwater or reservoir calculations. A 70 kg person standing on one heel (area ~5 cm² = 5×10⁻⁴ m²) exerts P = 686 / 5×10⁻⁴ ≈ 1.37 MPa — far higher than standing on both flat feet. At 10 m depth in seawater (ρ ≈ 1,030 kg/m³), added pressure = 1,030 × 9.81 × 10 ≈ 101 kPa ≈ 1 atm.

Worked example: A hydraulic piston with F = 8,000 N and A = 0.02 m² produces P = 8,000/0.02 = 400,000 Pa = 400 kPa ≈ 4 bar ≈ 58 psi. A SCUBA diver at 30 m fresh water (ρ = 1,000) faces gauge pressure ρgh = 1,000 × 9.81 × 30 = 294,300 Pa ≈ 2.9 atm above surface pressure.

Link to the ideal gas law for gas pressure-volume-temperature, the force calculator for F in P = F/A, and bar-to-psi or kilopascal-to-psi converters for international units. Weather barometric trends and tire inflation both use gauge pressure readings daily.