Pressure is just force spread over area.
Solve for pressure, force, or area with the relation P = F/A, then read the result in Pascals, kPa, psi, bar, atmospheres, and mmHg. Change any number and the whole report updates live.
The setup
What this pressure means
Pressure rises as the area shrinks
Pressure vs contact area, at the same force
Reference points
The same pressure in every unit
| Unit | Value | What uses it |
|---|
Pressure at different contact areas
Same force, spread over more or less area. Halve the area and the pressure doubles.
| Area (m2) | Area (cm2) | Pressure (Pa) | kPa | psi |
|---|
Pressure, explained
Understanding Pressure (P = F/A)
Pressure is defined as force per unit area: P = F/A. The SI unit is the Pascal (Pa), equal to one Newton per square meter. Pressure explains why a sharp knife cuts easily (small area, high pressure) and why snowshoes prevent sinking (large area, low pressure). The concept applies to fluids, gases, and solids.
Pressure Unit Conversions
Common pressure units include Pascals (Pa), pounds per square inch (psi), bar, atmospheres (atm), kilopascals (kPa), and millimeters of mercury (mmHg). One atmosphere equals 101,325 Pa, 14.696 psi, 1.01325 bar, or 760 mmHg. Tire pressure is typically measured in psi, weather in millibars, and blood pressure in mmHg.
Common questions
What is a Pascal?
A Pascal (Pa) is the SI unit of pressure, equal to one Newton per square meter. It is a very small unit, atmospheric pressure is about 101,325 Pa, which is why kilopascals (kPa) and other units are often used in practice.
How do I convert psi to bar?
Divide psi by 14.5038 to get bar. For example, 30 psi = 2.07 bar. Alternatively, multiply bar by 14.5038 to get psi. Tire pressure of 32 psi equals about 2.21 bar.
What is atmospheric pressure?
Standard atmospheric pressure at sea level is 101,325 Pa (1 atm). This is the pressure exerted by the weight of the atmosphere above us. It decreases with altitude, at 5,500 meters, pressure is roughly half of sea level.
Results assume a uniform force spread evenly over the contact area. Real pressures vary across a surface and can concentrate at edges and points. Gauge readings also depend on the local atmosphere. Use these figures for study and planning, not for safety-critical engineering.