FPE Calculator (Foot-pounds of Energy)

Find muzzle energy in foot-pounds from grains and feet per second.

Energy (ft·lb) 364.23

Formula: FPE = grains × fps² ÷ 450,240

Step-by-step with your numbers:

1. Values used:

2. Projectile weight = 124 gr

3. Velocity = 1,150 fps

5. Energy = 364.23ft·lb

Did we solve your problem today?

Foot-pounds of energy (FPE) is the standard way US shooters express muzzle energy.

The math behind it

FPE = grains × velocity² ÷ 450,240. The constant folds in the grain-to-pound and unit conversions.

124 gr at 1150 fps → about 364 ft·lb.

How many grains in a pound?

7000 grains make one pound.