Library / Foundations: Physics / FPH-13
Foundations: Physics
Pressure from force and area
Pressure exerted by a force over an area.
- Ref
- FPH-13
- Rev
- v1
- Field
- Foundations: Physics
- Result
- p [kPa]
Pressure in pascals uses perpendicular force in N and area in m². The calculator takes area in cm².
Pressure is how concentrated a force is: the same force on a smaller area gives a bigger pressure.
Calculator
kPa
N
cm²
- Pressure in pascals40,000 Pa
- Pressure in bar0.4 bar
What drives the result
Each variable is moved across its typical range while the others stay at the values above. The longest bar is the key driver.
Pressure (kPa) current value 40 kPa
FPerpendicular forceKey driver
0.06676,670
AArea
1.26,000
- Spreading a load over a larger area (snowshoes, tracks) reduces pressure.
- Sharp points concentrate force into a very small area.
Chart data as tables
Ranked variables
| Variable | Typical range | Lowest result | Highest result | Swing (kPa) | Local step | Change in result |
|---|---|---|---|---|---|---|
| F Perpendicular force | 1 to 100,000 N | 0.06667 | 6,667 | 6,667 | +10% | +10 % |
| A Area | 1 to 5,000 cm² | 1.2 | 6,000 | 5,999 | +10% | −9.09 % |
Sweep of Area
| Area (cm²) | Pressure (kPa) |
|---|---|
| 1 | 6,000 |
| 2.9 | 2,069 |
| 8.409 | 713.5 |
| 24.38 | 246.1 |
| 70.71 | 84.85 |
| 205 | 29.26 |
| 594.6 | 10.09 |
| 1,724 | 3.48 |
| 5,000 | 1.2 |
Sweep one variable
Pressure (kPa)Hover, touch, or use the arrow keys on the chart
Variables and how each one contributes
p
Pressure
What the equation gives you. Everything else feeds it.
F
Perpendicular force
Force at right angles to the surface. Directly proportional.
A
Area
Contact area. Inversely proportional.
Worked example with the values above
- Convert area: 150 cm² = 0.015 m².
- p = F/A = 600 / 0.015 = 40,000 Pa.
- In kilopascals 40 kPa.
Assumptions and limits
- Force perpendicular to the surface.
- Force spread uniformly.
Common mistakes
- Mixing cm² and m².
- Using weight when the force is not vertical.
Statistics and uncertainty
Area is hard to measure for irregular contacts and often the major error.
Where it is used
- Ground pressure of vehicles.
- Hydraulic and pneumatic systems.
Maths you need
- Area: m² and cm²
- Force: newtons