AirGun Power Calculator

AirGun Power Calculator

Use the airgun power calculator below to work out the foot pound energy (muzzle energy) or feet per second (velocity).

Click here for velocity
Foot Pound Energy
Feet Per Second

Foot Pound Energy (muzzle energy)

Calculate your airgun’s foot-pound power. Input pellet weight (in grains) and muzzle velocity (ft/sec).

What Does Foot Pound Energy Mean (FPE)?

Foot pound energy (FPE) quantifies the kinetic energy a pellet carries upon impact. It’s a measure of the potential damage or impact force the pellet can deliver, making it particularly relevant for hunting or pest control.

How To Work Out Foot Pound Energy

Measuring FPE requires knowing the pellet’s velocity and weight. Use a chronograph to determine velocity, then apply the formula: Energy = Pellet Weight * Velocity^2 / 450240.

Ensure pellet weight is in grains and velocity is in feet per second for accurate results.

What Does The Feet Per Second Of An Airgun Mean (FPS)?

Feet per second (FPS) is a measure of how fast the pellet travels through the air from the airgun to the target.

How To Measure Your Rifle’s Feet Per Second

To accurately measure FPS, use a chronograph placed approximately 9 inches in front of the muzzle.

Ensure the air rifle is stable and fire a pellet through the chronograph’s sensors. Repeat several times for consistency and calculate the average for a reliable FPS measurement.

How To Work Out The Rifle’s Feet Per Second (velocity)

If you know the FPE, you can work out the FPS using the pellet weight and the energy output. The formula is: Velocity = Square root of (Energy * 450240 / Pellet Weight).


  • FPS (Feet Per Second): The speed at which a pellet travels through the air from the gun to the target.
  • FPE (Foot Pound Energy): A measure of the kinetic energy a pellet carries upon impact, indicating the potential impact force.
  • Chronograph: A device used to measure the speed of a projectile, crucial for accurately determining FPS.
  • Kinetic Energy: The energy a body possesses by virtue of being in motion, calculated in the context of airguns as FPE.
  • Pellet Weight: The mass of an airgun pellet, typically measured in grains,
  • Velocity: The speed of the pellet upon exiting the muzzle, measured in feet per second (FPS).
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