Pressure Calculator: P = F / A
Solve pressure, force or area from the other two. Use Pa, kPa, bar, psi or atm and see the formula P = F / A with each step. Free and private, runs in your browser.
Fill in all but one field: the empty field is the one you solve for.
About the Pressure Calculator
The Pressure Calculator solves P = F ÷ A for pressure, force or area. Enter any two of Pressure, Force and Area and the third appears as you type, with the formula in standard notation, the solved symbol highlighted and a one-line substitution such as 500 N ÷ 0.25 m² = 2,000 Pa.
Pressure measures how concentrated a force is. The same force spread over a large area produces a small pressure, and squeezed into a small area it produces a large one. That is why a sharp knife cuts better than a blunt one, why snowshoes keep you on top of the snow, and why a high-heeled shoe can dent a floor that a flat shoe leaves alone.
How to use the pressure calculator
Steps
- Fill in two fields and leave the one you want to find empty.
- Choose units. Pressure offers Pa, kPa, MPa, bar, psi, atm and mmHg, force offers N, kN and lbf, and area offers m², cm², in² and ft².
- Read the answer under the formula. Change the unit of the empty field to see it in another unit.
- Press Clear all to reset.
Area must be greater than zero, and a message appears beside the field if it is not. Pressure and force may be negative, for example a gauge pressure below atmospheric. If all three fields are filled, clear one, and with fewer than two the calculator shows a hint.
Formula
P is pressure, F is the force acting perpendicular to the surface, and A is the area it acts on. One pascal is one newton per square metre. The force must be perpendicular to the surface; for a slanted force, use only the component at right angles to it.
Worked examples
Example 1: find the pressure
A 500 N force presses on an area of 0.25 m². The pressure is P = 500 ÷ 0.25 = 2,000 Pa, or 2 kPa.
Example 2: find the force
Atmospheric pressure is 101,325 Pa, so the air pushes on a 1 m² surface with F = 101,325 × 1 = 101,325 N.
Example 3: find the area
A force of 1,000 N must produce a pressure of 200 kPa. The area is A = 1,000 ÷ 200,000 = 0.005 m², which is 50 cm².
Useful reference values
- 1 atm = 101,325 Pa, which is also 1.01325 bar and about 14.696 psi.
- 1 bar = 100,000 Pa, close to atmospheric pressure at sea level.
- A typical car tyre is inflated to roughly 30 to 35 psi, around 210 to 240 kPa.
Privacy
Nothing is uploaded; every calculation runs in your browser and never leaves your device.
Related tools
The Pressure Converter changes between pascals, bar, psi and more, the Area Converter translates square units, and the Force Calculator finds the force itself from mass and acceleration.
Frequently asked questions
How do I calculate pressure?
Divide force by area: P = F ÷ A. A 500 N force on 0.25 m² gives 2,000 Pa. Enter the force and area and leave pressure empty.
How do I find the force or the area?
Leave that field empty. Force equals pressure times area, and area equals force divided by pressure. For example, 1,000 N at 200 kPa needs an area of 0.005 m², which is 50 cm².
Which pressure units are available?
Pressure offers Pa, kPa, MPa, bar, psi, atm and mmHg. Force offers N, kN and lbf, and area offers m², cm², in² and ft². Choose the unit of the empty field to see the result converted.
Why does a smaller area give a higher pressure?
The same force is concentrated on less surface, so each unit of area carries more of it. That is why a needle pierces what a finger cannot, and why snowshoes help you stay on top of snow.
What does one pascal mean?
One pascal is one newton of force on one square metre. Atmospheric pressure at sea level is about 101,325 Pa, or 101.325 kPa, so it is large compared with a pascal.
Can pressure or force be negative?
Yes, for example a gauge pressure below atmospheric. Area must be greater than zero, and the calculator shows a message next to the field if it is not.
Is my data kept private?
No. The force, area and pressure you enter are calculated locally in your browser, and nothing is uploaded, stored or shared with a server, so any private engineering figures stay on your device.