Pressure Calculator
Calculate pressure from force and area, in pascals, atm, and psi.
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About this calculator
What Is Pressure?
Pressure is the force applied perpendicular to a surface, spread over the area it acts on: P = F ÷ A. The SI unit is the pascal (Pa), equal to one newton per square meter. Because the area is in the denominator, the same force can produce very different pressures — a sharp knife cuts easily because its tiny edge concentrates the force, and snowshoes keep you on top of snow by spreading your weight over a large area. This pressure calculator finds pressure, force or area from the other two values.
The Pressure Formulas
- Pressure = Force ÷ Area
- Force = Pressure × Area
- Area = Force ÷ Pressure
A 500 N force pressing on 0.25 m² creates 2,000 Pa of pressure, or 2 kPa. Keep units consistent: newtons with square meters give pascals, while pounds-force with square inches give psi.
Pressure Units You Will Meet
- Pascal (Pa) and kilopascal (kPa) — SI units; weather maps often use hectopascals (hPa).
- Bar and millibar — 1 bar = 100,000 Pa, close to atmospheric pressure.
- Atmosphere (atm) — 1 atm = 101,325 Pa at sea level.
- psi (pounds per square inch) — tire pressure and many US industrial gauges; 1 psi ≈ 6,895 Pa.
- mmHg / torr — blood pressure and vacuum work.
Where Pressure Matters
Tire pressure affects safety and fuel economy; hydraulic systems multiply force by using pressure on pistons of different sizes; and fluid pressure rises with depth — roughly one extra atmosphere for every 10 meters of water. Gas pressure also depends on temperature and volume, which is the subject of the gas laws.
Pressure and Force
If you only need the force side of the equation, the Force Calculator uses Newton's second law, and the Density Calculator helps with the mass-and-volume side of fluids. For converting between units like psi, bar and kPa, use the Unit Conversion Calculator.
Worked example
500 newtons spread over 2 square meters produces 250 pascals of pressure — about 0.0025 atmospheres, or 0.036 psi.
Frequently asked questions
What is the formula for pressure?
Pressure equals force divided by the area it's applied over (P = F/A).
Why does the same force produce different pressure?
Because pressure depends on area too — spreading a force over a larger area lowers the pressure, which is why snowshoes work.
What's the difference between pascals, atm, and psi?
They're different units for the same physical quantity — pascals are the SI unit, atm is relative to standard atmospheric pressure, and psi (pounds per square inch) is common in the US.
What's a typical value for atmospheric pressure?
About 101,325 pascals, 1 atm, or 14.7 psi at sea level.
