How this calculator works
Pounds per square inch means pounds-force divided by square inches, not pounds of mass divided by length. This tool computes the rectangular area from length and width, then applies average normal pressure. Each input may use a supported unit; the engine converts force, lengths and pressure before calculation. The output starts in psi and can be switched to other pressure units.
Formula
P = F/(length times width); 1 psi = 6894.757293168 Pa.
Worked example
A 1000 N force spread over 0.1 m by 0.2 m gives 50000 Pa, about 7.252 psi. One pound-force acting on a 1 inch by 1 inch square gives 1 psi.
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Frequently asked questions
Is lbf the same as lb?
A pound-force is a force; a pound is a mass. Use a force value or convert mass through an appropriate gravity.
Can I use this for tyre pressure?
It converts pressure units, but a tyre gauge reading cannot generally be inferred from the tyre footprint alone.
Does average pressure describe sharp contact peaks?
No. Local contact pressure can vary substantially even when the average force-to-area ratio is known.