Airgun Calculators

Muzzle Energy

Muzzle energy is commonly referred to as the Power of your air rifle.  In the UK and USA this is measured as Foot-Pounds of Energy (FPE).  IF you are looking to buy an air rifle / pistol from Europe (and other Countries) you will see them being advertised as a power output in Joules.

The equation used to calculate it is;

FPE = Pellet Weight * FPS2/(2 * Gravity Acceleration) * (Grains/lb)

You can grab your calculator if you like or just pop the details in the calculator to the right, this will automatically generate the Power output of your rifle.

For reference, 1 is 1.35581795 Joule.

Pellet Weight

Airgun pellets are often sold with their weight represented in grains, which is all very well if you lived in the 1700’s, but most household weighing devices use metric grams.  Bear in mind that a pellet weighing 8 gr is about 0.52 of a gram, if you’re buying weighing equipment to measure pellets, you’re going to need something that can measure down to 0.0001 gram for any real accuracy.  0.001 gram increments sill suffice for most shooters though.

To get an average grain weight, weigh 100 pellets to get your total weight in grams and pop the details in the first box to the right, and it’ll automatically calculate individual gr. weigh on average.


Unit Conversions

Different folks use different measurements… mainly down to the prevalence of metric and imperial measurements commonly in use in modern society.

With that in mind here’s a few common measurement units used in air-gunning to help you out.  All you need to do is pop the measurement you have in the first box and select the measurement you’d like from the list.


If there’s any other conversion or calculators you’d like to see, drop a quick note on the forum here and postup a request.  We’ll certainly try and accommodate where we can 😎

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