Pressure Calculator (P = F/A)Free online science calculator — instant results, no sign-up
Calculate pressure from force and area.
About the Pressure Calculator (P = F/A)
The Pressure Calculator (P = F/A) calculates average pressure by dividing the force acting perpendicular to a surface by its area. Enter force in newtons and area in square metres to see pressure in pascals, kilopascals, and psi. With the default force of 200 N and area of 0.5 m², the pressure is 400 Pa.
- Force (N)
- The force acting perpendicular to the surface, measured in newtons (N), with a default value of 200.
- Area (m²)
- The surface area over which the force acts, measured in square metres (m²), with a default value of 0.5.
Formula and method
P = F / A; P_kPa = P / 1000; P_psi = P / 6894.757293168. With the defaults: P = 200 / 0.5 = 400 Pa; P_kPa = 0.4 kPa; P_psi ≈ 0.058 psi.
- PAverage pressure in pascals (Pa), where 1 Pa = 1 N/m².
- FForce perpendicular to the surface, in newtons (N).
- AArea over which the force acts, in square metres (m²).
- P_kPaThe calculated pressure expressed in kilopascals (kPa).
- P_psiThe calculated pressure expressed in pounds-force per square inch (psi).
Divide the perpendicular force in newtons by the area in square metres to obtain pressure in pascals. Convert that result to kilopascals by dividing by 1000 and to psi by dividing by approximately 6894.757293168. Round the converted values for display; the default result in psi is approximately 0.058.
Worked example
These are the calculator's starting values and the results it actually produces for them.
Inputs
- Force200 N
- Area0.5 m²
Results
- Pressure400 Pa
- In kilopascals0.4 kPa
- In psi0.058
How to use the Pressure Calculator (P = F/A)
- 1Enter the perpendicular force in Force (N), or retain the default 200 N.
- 2Enter the area carrying that force in Area (m²), or retain the default 0.5 m²; the area must be greater than zero.
- 3Calculate pressure using P = F/A: the defaults give 200 / 0.5 = 400 Pa.
- 4Read the equivalent outputs: 400 Pa, 0.4 kPa, and approximately 0.058 psi.
Reading your result
The Pressure row reports force per unit area in pascals: 400 Pa means 400 newtons per square metre. The In kilopascals row expresses the same pressure as 0.4 kPa. The In psi row expresses it as approximately 0.058 pounds-force per square inch. These are three unit representations of the same pressure, not separate physical quantities.
Limitations
P = F/A gives average pressure over the entered area; it does not describe local pressure variations unless the load is uniformly distributed. Use the component of force perpendicular to the surface, not a tangential force, and use a positive area. For ordinary compressive loading, enter a nonnegative force magnitude. The calculation does not automatically add atmospheric pressure or distinguish gauge from absolute pressure; that depends on what the entered force represents. Displayed conversions may be rounded, and result accuracy depends on the input measurements.
Common questions
Why do 200 N and 0.5 m² produce 400 Pa?+
Pressure is force divided by area, so 200 N / 0.5 m² = 400 N/m². Since one newton per square metre equals one pascal, the result is 400 Pa.
Why is the psi output only 0.058 when the pressure is 400 Pa?+
A psi is a much larger pressure unit than a pascal: 1 psi is approximately 6894.757 Pa. Dividing 400 Pa by that conversion factor gives approximately 0.058 psi.
Which area should I enter when an object presses against a surface?+
Use the contact area over which the entered force is transmitted, expressed in square metres, rather than the object's total exterior area. For the same force, a smaller contact area produces a higher average pressure.
Can I enter a force that acts at an angle to the surface?+
First resolve the force into its perpendicular component. If θ is measured from the surface normal, enter F_total × cos(θ); the tangential component does not contribute to the normal pressure calculated by this tool.
Does the calculator save my information?+
Calculations run in your browser. While signed in, inputs and results are automatically recorded in account history; saving a result creates a separate saved record.
Further reading
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Results are estimates for informational purposes and are not financial, medical or legal advice.