Pressure Calculator
Pressure from a force spread over an area, P = F ÷ A, or the force a pressure exerts on an area, or the area a force needs to reach a pressure.
Result
Pressure: 100 psi
The average over the area, as if the force were spread evenly across it.
- In bar and atmospheres
- 6.895 bar (6.805 atm)
- Force
- 100 lbf (444.8 N)
- Area
- 1 in² (0.006944 ft²)
https://calcgallery.com/physics/pressure-calculator/
Results come from the published equations applied to the values you enter. They are not electrical design, conductor sizing, laboratory safety or medical guidance. Weather indices describe a standard person in standard conditions and are not a forecast. Where codes apply, local rules vary and must be checked. Read the full disclaimer
How to use the Pressure Calculator
- Choose whether to find the pressure, the force or the area.
- Enter the other two. The force is the part acting straight onto the surface.
- Read the pressure in psi or kilopascals, with the same figure in bar and atmospheres.
The formulas
P = F ÷ AF = P × AA = F ÷ PWith the force in newtons and the area in square metres, the pressure is in pascals. A pound-force on a square inch is one psi.
Limits
The force is taken as spread evenly and acting at right angles to the surface. Where it is concentrated at a point or an edge, the local pressure there is far higher than this average. The page says nothing about what pressure a tyre, a vessel, a pipe or a floor can take; that comes from its maker or the rules that apply.
With your numbers
- P = F ÷ A = 100 lbf ÷ 1 in² = 100 psi
Quick reference
The average over the area, as if the force were spread evenly across it.
| Example | Result |
|---|---|
| 100 lbf on 1 in² | Pressure: 100 psi |
| 700 N on 0.05 m² | Pressure: 14 kPa |
| Dam, 1.568 × 10¹⁰ N on 40,000 m² | Pressure: 392 kPa |
| Force of 30 psi on 10 in² | Force: 300 lbf |
| Force of 200 kPa on 0.01 m² | Force: 2,000 N |
| Area for 1,000 N at 200 kPa | Area: 50 cm² |
Common questions about the Pressure Calculator
- How do I calculate pressure from force and area?
- Divide the force by the area it is spread over: P = F ÷ A. 100 lbf on one square inch is 100 psi, about 689.5 kPa. 700 N spread over 0.05 m² is 14,000 Pa, or 14 kPa. A pascal is one newton per square metre.
- Why does a small area give a high pressure?
- The same force shared over less area puts more on each part of it. A knife cuts because its edge is narrow, and snowshoes keep you on top of snow because they are wide. Halve the area and the pressure doubles.
- How do I find the force a pressure exerts?
- Multiply the pressure by the area: F = P × A. 30 psi acting on 10 in² pushes with 300 lbf. OpenStax University Physics example 14.1 finds the force on a dam from its average water pressure, 392 kPa, over 4.00 × 10⁴ m²: about 1.57 × 10¹⁰ N.
- How do psi, kPa, bar and atmospheres compare?
- One psi is about 6.895 kPa. One bar is exactly 100 kPa, and one standard atmosphere exactly 101.325 kPa, about 14.7 psi. The page shows the result in all of them, but it is a formula page, not a unit converter.
- Is this gauge pressure or absolute pressure?
- Neither in particular: it is the pressure the force produces over the area. A tyre gauge reads pressure above the surrounding air, while absolute pressure includes the atmosphere as well; add or subtract the air pressure yourself if you need to switch between them.