Calculate pressure, force or area with the formula P = F ÷ A. Fill in two of the three fields and leave the third at 0, and the calculator works out the rest.
Pressure (P) is the force (F) acting spread over an area (A). Pressure is measured in pascals (Pa), where 1 Pa equals a force of 1 Newton spread over 1 square meter.
This is why skis and snowshoes work: by spreading your body weight over a much larger area than under a regular shoe, the pressure against the snow is reduced greatly, so you sink less even though the force (your weight) is exactly the same.
Skis spread your weight over a much larger area than a boot sole alone. Since pressure is force divided by area, the pressure against the snow becomes much lower with skis on, even though the force (your weight) is unchanged. Lower pressure means you sink less into the soft snow.
Pascal (Pa) is the SI unit for pressure, defined as 1 Newton per square meter. Bar is a larger, more practical unit often used for example for tire pressure: 1 bar equals 100,000 Pa, roughly equal to atmospheric pressure at sea level.
Pressure and area are inversely proportional when force is held constant: double the area the force is spread over, and pressure is halved. That's why a sharp knife blade (small area) cuts more easily than a dull blade (larger area) with the same force behind it.