Enter the weight (grains) and the velocity (fps) into the calculator to determine the FPE.

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 or energy
  • V is the velocity of the projectile (ft/s)
  • W is the weight of the projectile (grains)

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