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FPE Calculator


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FPE calculator helps you calculate how much power a moving object has based on its speed and weight. It helps airgun enthusiasts determine the muzzle energy of their shots and helps them choose the right ammunition for different targets and needs.

FPE Formula:

\(\text{FPE} = \frac{\text{V}^2 \cdot \text{W}}{450240}\)


  • FPE – Represents Foot-Pounds of Energy, measured in foot-pounds (ft-lb)
  • V – Represents the velocity of the projectile, measured in feet per second (ft/s)
  • W – Represents the weight of the projectile, measured in (grains)
  • 450437 – Represents the conversion factor between grains and foot pounds

FPE Example:

Let’s say, we have a scenario where a projectile (like a bullet) is moving at a velocity (V) of 100 feet per second (fps), and the projectile has a weight (W) of 200 grains.

FPE calculator

Now, using the formula:

\(\text{FPE} = \frac{\text{V}^2 \cdot \text{W}}{450240}\)

How to calculate FPE?

  • First, we square the velocity of the projectile: 100 * 100 = 10,000
  • Then, we multiply the squared velocity by the weight: 10,000 * 200 = 2,000,000
  • Finally, we divide the result by 450240: 2,000,000 / 450240 ≈ 4.44 (approximately)

Therefore, when the projectile moves at 100 fps with a weight of 200 grains, it would have around 4.44 Foot-Pounds of Energy (FPE).

Common Examples of FPE:

Scenario Pellet Weight (grains) Velocity (ft/s) FPE (ft-lb)
Hunting small game (squirrel, rabbit) 7.9 850 16.9
Plinking targets (cans, paper) 5.5 700 10.5
Long-range shooting (30+ yards) 10.5 900 29.7
Pest control (birds, rodents) 8.2 1000 33.3
Target practice (competition) 7.0 800 14.0
High-powered PCP air rifle 14.3 1200 71.3
Low-powered CO2 pistol 4.5 500 5.0
Customized air gun setup 10.0 850 22.2
Backyard target shooting 6.5 750 11.8
Pest control (larger bird species) 12.0 1050 44.1

Alan Walker

Studies mathematics sciences, and Technology. Tech geek and a content writer. Wikipedia addict who wants to know everything. Loves traveling, nature, reading. Math and Technology have done their part, and now it's the time for us to get benefits.

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