Enter the diameter of the piston, the diameter of the rod, and the pressure between the piston and rod into the calculator to determine the retraction force.

## Retraction Force Formula

The following equation is used to calculate the Retraction Force.

RF = P (pi*Dp^2/4 - pi*Dr^2/4)
• Where RF is the reaction force (lbf)
• P is the pressure between the piston and rod (psi)
• Dp is the diameter of the piston (in)
• Dr is the diameter of the rod (in)

To calculate the retraction force, subtract the area of the rod from the area of the piston, then multiply by the pressure.

## What is a Retraction Force?

Definition:

A retraction force is a total force required to retract a pneumatic cylinder with with a piston and rod.

## How to Calculate Retraction Force?

Example Problem:

The following example outlines the steps and information needed to calculate the Retraction Force.

First, determine the pressure. For this example, the pressure is 50 psi.

Next, determine the diameter of the piston. In this case, the diameter of the piston is found to be 5 in.

Next, determine the diameter of the rod. For this problem, the diameter of the rod is measured to be 2 in.

Finally, calculate the Retraction Force using the formula above:

RF = P (pi*Dp^2/4 – pi*Dr^2/4)

RF = 50* (3.14159*5^2/4 – 3.14159*2^2/4)

RF = 824.66 lbf