Pressure Calculator (P = F/A)
Pick what you want to find, enter the other two values with their units, and read the pressure in several units at once.
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Formula
P = F / A, so F = P × A and A = F / P
- P is pressure in pascals (Pa), F is force in newtons (N) and A is area in square metres (m²).
- 1 bar = 100,000 Pa, 1 atm = 101,325 Pa, 1 psi = 4.4482216 N / 0.00064516 m² = 6894.757 Pa.
- 1 lbf = 4.4482216 N and 1 kgf = 9.80665 N.
Worked example
A force of 1000 N acts on an area of 0.5 m²:
P = 1000 / 0.5 = 2000 Pa
That is 2 kPa, 0.02 bar, 0.2901 psi or 0.01974 atm.
Solving the other way: 2 bar (200,000 Pa) on 50 cm² (0.005 m²) gives F = 200,000 × 0.005 = 1000 N.
Frequently asked questions
What is the pressure formula?
Pressure is force divided by the area it acts on: P = F / A. A force of 1000 N spread over 0.5 m² gives 1000 / 0.5 = 2000 Pa, which is 2 kPa.
How do I find force or area from pressure?
Rearrange the formula: F = P × A and A = F / P. For example, 2 bar (200,000 Pa) acting on 50 cm² (0.005 m²) pushes with 200,000 × 0.005 = 1000 N.
How do I convert between pascals, bar, psi and atm?
1 bar is 100,000 Pa, 1 atm is exactly 101,325 Pa and 1 psi is about 6894.757 Pa. So 150 lbf on 10 in² is 15 psi, which is 103,421 Pa or about 1.02 atm.
Why does a small area give a large pressure?
The same force concentrated on less area means a higher pressure. 100 N on 1 cm² (0.0001 m²) is 1,000,000 Pa, while the same 100 N on 1 m² is only 100 Pa, which is why knives and nails work.