Enter the weight (grains) and the velocity (fps) into the calculator to determine the FPE. This calculator can also determine the weight or velocity if the other variables are known.

## FPE Formula

The following formula is used to calculate the foot-pounds energy (FPE) of a projectile.

FPE = V^2 * W / 450240
• Where FPE is the foot-pounds of energy
• V is the velocity of the projectile (ft/s)
• W is the weight of the projectile (grains)

To calculate FPE, square the project velocity, multiply the result by the weight in grains, then divide by 450240.

## FPE Definition

FPE is short for foot-pounds of energy. This term is used to describe the kinetic energy contained in a projectile.

## Example Problem

How to calculate FPE?

1. First, determine the velocity of the projectile.

For this example, the projectile is moving at 700 ft/s.

2. Next, determine the weight of the projectile.

The projectile, a pellet, in this case, weighs 12.5 grains.

3. Finally, calculate the FPE.

Using the formula above, the foot-pounds of energy is calculated as:
FPE = V^2 * W / 450240
FPE = 700*700&12.5/450240
FPE = 13.603