What next?
Pressure is force over area. These handle fluids and materials.
How to use this calculator
- Enter the force in newtons.
- Enter the area it acts on.
- Read the pressure in pascals and other units.
What your result means
Pressure is force spread over area (P = F ÷ A), in pascals. The same force on a smaller area gives higher pressure — which is why a sharp blade cuts. Results also show bar and psi for convenience.
Why this one is different
An area of zero is refused with a message instead of being reported as infinite pressure, which is the state a half-filled form is usually in. When both boxes hold sensible numbers the same pressure appears in pascals, kilopascals, bar and pounds per square inch together, so a tyre gauge and a datasheet can be compared without a second conversion.
Why a sharp knife cuts and a blunt one crushes
Pressure is force squeezed into an area — shrink the area and the pressure soars. It’s why a sharp blade slices effortlessly, why snowshoes stop you sinking, and why a stiletto heel dents a floor a heavy elephant wouldn’t.
The same principle runs through tyres, hydraulics and weather systems. Get comfortable with force-over-area and a lot of everyday physics clicks into place.
How it works
Pressure is how concentrated a force is over an area. The same force over a smaller area gives higher pressure — which is why a sharp knife cuts better than a blunt one. The SI unit is the pascal (one newton per square metre).
Formula
Worked example
A load of 800 N spread over 0.02 m²:
P = 800 ÷ 0.02
P = 40,000 Pa (40 kPa, or 0.4 bar)
The same 800 N on a 1 cm² point would be 8 MPa — 200 times higher. Pressure is why a drawing pin works and a snowshoe does not sink.
Frequently asked questions
How big is one bar?＋
One bar is 100,000 pascals, very close to average atmospheric pressure at sea level.
What is psi used for?＋
Pounds per square inch is common for tyre and gas pressures, especially in the US and UK. 1 psi ≈ 6,895 Pa.
How do I convert pascals to bar and psi?＋
One bar is exactly 100,000 Pa and one psi is 6,894.76 Pa. So the 40 kPa in the example is 0.4 bar or about 5.8 psi. As rough working figures, divide kPa by 100 for bar and by 6.9 for psi.
What is the difference between gauge and absolute pressure?＋
Gauge pressure is measured relative to atmospheric, so a tyre at 32 psi gauge is about 46.7 psi absolute. Most instruments read gauge, but thermodynamic calculations need absolute.
Why do tyre pressures change with temperature?＋
Because pressure in a fixed volume rises with absolute temperature. A rough rule is about 1 psi per 10 degrees Fahrenheit, which is why tyres should be checked cold.
Which pressure unit should I use?＋
Pascals for calculations, since it is the SI unit and keeps formulas consistent. Bar and psi are more convenient in the field, and the conversions are one bar to 100 kPa and one psi to 6.895 kPa.
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Assumptions & limitations
Engineering formulas are exact; the situations they model are not. Read your result with these limits in mind:
- Assumes the force is distributed evenly over the whole area. Uneven contact concentrates pressure at the high spots.
- Gives gauge pressure relative to your inputs — add atmospheric pressure (101.325 kPa at sea level) if you need absolute pressure.
- The force must act perpendicular to the surface; an angled force needs its normal component first.
- 1 bar = 100,000 Pa and 1 psi ≈ 6,895 Pa. Mixing these up is the most common error in pressure work.