# Pressure Calculators

Pressure is defined as the perpendicular force applied to a unit of area. Pressure quantifies the difference between the force applied to the head of a pin and the force of the tip of the pin going into the material. In the instance of a pin, the same force is applied to the head of the pin as the tip, however as the force is spread out across an area far bigger than the tip, it is the material at the tip end that yields instead of the head end.

## Pressure EquationThis pressure calculator uses a formula which derives pressure from the force applied and the area it is applied to. Pressure is defined as the perpendicular force applied to a surface divided by the area the force is applied to:
Where:
p = Pressure F = Force A = Surface Area |
The Pressure Equation can also be rearranged to find force and area:
## Force From Pressure Equation## Area From Pressure Equation |

The SI unit of Pressure is Pascals, however Pressure has many units, and it is also measured in two different ways:

## Absolute pressure

Absolute Pressure is the pressure of a system relative to a perfect vacuum. Using our SI units, a prefect vacuum in absolute terms would be 0 Pa. Ambient Absolute Pressure at sea level is 101325Pa.

## Gauge Pressure

Gauge or Gage Pressure which is more commonly used is the pressure of a vessel relative to the ambient pressure of the system. Ambient pressure at sea level on earth is 101325Pa, so when we talk about Gauge pressure, we are ignoring the ambient pressure. For example, a Gauge pressure of 101325pascals would be equivalent to 14.7PSI. In absolute pressure terms, this very same pressure would be 202650Pa.

## Example 1:

If a cubic vessel with pressure applied to all sides:

The total surface area of the cube and the areas the forces are applied is equal to the surface area of all sides, in this case each side = 1m2, over 6 sides this equals 6m2. The Combined force is 6 x 100N = 600N. Using the pressure calculator, we can see that 600N divided by 600N is equal to 1N/m2, or 1 Pascals.

## Example 2:

If the same vessel was used to contain pressure, as a pressure vessel is designed to do, the following would apply:

In this case, we need to use the rearranged pressure calculator to find the force applied to each side:

The area = 6m2 as before, but this time we know the pressure is 6894Pa. multiplying these together gives us a total force of 41364N, or when divided by 6, 6894N per side.

The area = 6m2 as before, but this time we know the pressure is 6894Pa. multiplying these together gives us a total force of 41364N, or when divided by 6, 6894N per side.