Find pressure from force and area (P = F/A), or the fluid pressure at a depth with P = ρgh, and see it in Pa, kPa, bar, atm, psi and mmHg at once. Handy for physics homework, tyres, diving and water tanks.
Pressure formulas
Worked examples
- A 60 kg person (≈ 600 N) standing on 4 cm² of stiletto heel exerts 600 ÷ 0.0004 = 1.5 MPa, more than an elephant’s foot. Spread over 400 cm² of shoe sole, it’s only 15 kPa.
- At 10 m under the sea, gauge pressure is 1025 × 9.81 × 10 = 100.6 kPa, about one extra atmosphere, so a diver feels roughly 2 atm in total.
Frequently asked questions
How do you calculate pressure?
Divide force by the area it acts on: P = F/A. 100 N on 0.5 m² gives 200 Pa.
How does water pressure change with depth?
It increases by ρgh: about 9.8 kPa per metre in fresh water and 10.1 kPa per metre in seawater, roughly 1 atm every 10 m.
What is the difference between gauge and absolute pressure?
Gauge pressure is measured relative to the atmosphere (tyre gauges read this). Absolute pressure adds atmospheric pressure, about 101.3 kPa at sea level.
How do I convert psi to bar?
1 bar = 14.504 psi, so divide psi by 14.504. Every result here is shown in Pa, kPa, bar, atm, psi and mmHg.
Related tools
Free educational tool by HawkInc. Results are calculated in your browser and rounded for display; check critical work by hand or with a second method.