Pressure Calculator

Pressure: P = F/A

Pressure is force per unit area: P = F/A, measured in pascals (1 Pa = 1 N/m²). Standard atmospheric pressure is 101,325 Pa = 1 atm = 760 mmHg = 14.7 psi = 1,013 hPa. The smaller the area, the higher the pressure — that's why a high heel (≈1 mm² contact) supporting 70 kg generates ≈70 MPa, far more than a car tire (200 kPa ≈ 30 psi). Blood pressure is reported in mmHg (systolic/diastolic, e.g., 120/80). Hydrostatic pressure follows P = ρ·g·h — every 10 m of water adds about 1 atm, which is why divers must equalize. Pascal's principle (pressure transmits fully through a confined fluid) underlies hydraulic presses and brakes.

Applications

Meteorology (hPa on weather maps), tire pressure, pressure cookers (≈1.8 atm), aviation (altimeters infer altitude from pressure), foundation engineering, hydraulic systems, scuba diving, and medical instruments (sphygmomanometers, ventilators).

FAQ

Why does a sharp knife cut better? Same force on a much smaller area means much higher pressure — the blade concentrates force into a thin edge.

Pa, bar, psi, atm — which to use? SI is Pa; bar (10⁵ Pa) is common in industry; psi in the US/tires; atm in chemistry. 1 bar ≈ 1 atm (within 1.3%).

Is pressure a vector? No — pressure is a scalar. The force it produces on a surface is a vector, always normal to the surface.