This pressure calculator solves P = F ÷ A — how concentrated a force is over an area. Find pressure, force or contact area, with instant conversions between pascals, kPa, bar, atmospheres and psi.
What Is Pressure?
Pressure is force spread over area: P = F ÷ A. The same force can be gentle or destructive depending on how concentrated it is — a thumb presses a drawing pin into the wall because all its force lands on a near-zero area, while snowshoes keep you on top of snow by doing the opposite. Pressure runs hydraulics, weather, diving and blood-pressure medicine. This calculator is part of our Physics Calculators collection; the force side is our Force Calculator.
Worked Example (Verified)
A 500 N force on 0.05 m²: P = 500 ÷ 0.05 = 10,000 Pa = 10 kPa (about 1.45 psi). Concentrate that same force onto a pin’s tip — say 1 mm² (0.000001 m²) — and the pressure becomes 500 million Pa, which is why pins pierce and palms do not.
Pressure Units and Reference Points
| Unit | In pascals | Where you meet it |
|---|---|---|
| Pascal (Pa) | 1 | SI unit; small — weather uses hPa |
| Kilopascal (kPa) | 1,000 | Tire ratings outside the US |
| Bar | 100,000 | Scuba tanks, espresso machines (9 bar) |
| Atmosphere (atm) | 101,325 | Sea-level air pressure ≈ 1 atm |
| psi | 6,894.76 | US tires (≈32 psi), pressure washers |
Reference points: the atmosphere pressing on you right now is ~101 kPa; a car tire holds ~220 kPa gauge; the bottom of the Mariana Trench exceeds 100 MPa — a thousand atmospheres.
Pressure in Fluids
Under water or any fluid, pressure grows with depth: P = ρ × g × h, the density relation from our Density Calculator. Every 10 m of water adds about one atmosphere — the fact that makes Boyle’s-law effects so strong for divers and that engineers use when sizing dams, which are thick at the bottom precisely because pressure is greatest there.
Related Tools
- Force Calculator — the F in P = F/A
- Density Calculator — for fluid pressure ρgh
- Physics Calculators — the full collection
Frequently Asked Questions
What is the formula for pressure?
P = F ÷ A: force divided by the area it acts on. In SI units, newtons ÷ square meters = pascals.
Why do sharp objects cut?
A sharp edge concentrates force onto a microscopic area, producing enormous pressure that exceeds the material’s strength. Bluntness is the opposite strategy.
How do I convert psi to kPa?
Multiply psi by 6.895. A 32 psi tire is about 221 kPa. The results cards above show all conversions automatically.
What is gauge vs. absolute pressure?
Gauge pressure is measured relative to the atmosphere (a flat tire reads 0 psi gauge but 14.7 psi absolute). This calculator works in absolute terms — state which you mean when comparing.
How does pressure change with depth?
It increases linearly: an extra ρgh for depth h. In water, roughly +1 atm every 10 meters.
Is this pressure calculator free?
Yes — free, instant, no sign-up.