Pressure calculator
Pressure, force or area from p = F ÷ A.
Fill in the fields and the result will appear here automatically.
Finds mean pressure from the normal force component and contact area, or solves for force or area. It does not calculate the pressure distribution: local values at edges or contact points can differ from the mean. The atmosphere row converts units using 1 atm = 101,325 Pa; it does not add ambient pressure. You supply any allowable bearing pressure; strength and settlement are not assessed.
How it works
Formula and logic
p = Fₙ/A is mean normal pressure; Fₙ = pA and A = Fₙ/p. Area is positive. Zero normal force gives zero pressure in the forward mode; zero pressure at a known area gives zero force. Finding a positive area requires Fₙ > 0 and p > 0. Pressure in atm is p/101325.
Example
1000 N on 2 m² gives 500 Pa. The same 1000 N on 1 cm², or 0.0001 m², gives 10,000,000 Pa = 10 MPa. At 2000 N and 100,000 Pa, the area is 0.02 m².
Fields and units
- What to find — list option
- Normal force — N
- Area — m²
- Pressure — Pa
- Area — m²
- Normal force — N
- Pressure — Pa
How to use
- — Choose pressure, force or area.
- — Use normal force in N and area in m²; resolve an inclined force into components first.
- — For area, provide positive force and pressure; the zero pair cannot determine area.
- — Convert cm² to m² by multiplying by 0.0001: 1 cm² = 0.0001 m².
Method and limitations
- Calculation method
- Formula and logic
- Data or methodology source
- OpenStax: mean pressure of normal force NIST: 1 standard atmosphere = 101,325 Pa
- Limitation
- Non-negative mean normal-pressure scenario; local stresses, foundation strength and automatic reference-pressure conversions are not calculated.
FAQ
Why does a wider support give lower mean pressure?
At fixed normal force, doubling area halves F/A. This does not describe local peaks or changes in ground properties.
Is this gauge or absolute pressure?
The form evaluates Fₙ/A without choosing a pressure reference. Converting gauge to absolute requires the actual ambient pressure, which need not be 101,325 Pa.
How can I use the inverse bearing-area calculation?
Enter force and a separately justified allowable mean pressure. A = F/p gives area within this simplified model, not a footing verification; non-uniform loading, stability and settlement are excluded.
Is this the same pressure unit as in a tyre or pipe?
Yes: Pa means N/m². A particular instrument may report absolute, gauge or differential pressure, so identify its reference before comparing.
Why can force be zero but area cannot?
Zero force on a positive area gives zero mean pressure. Zero area is a zero denominator; F = p = 0 does not identify a positive area.