What is Foot Pounds of Energy (FPE)?

What is Muzzle Energy?
Muzzle energy is the kinetic energy of a pellet or bb as it is ejected from the barrel of a handgun or rifle. This energy is measured and specified by Foot-Pounds of Energy or “FPE” (in Europe and Internationally they refer to energy as “Joules”), muzzle energy is much more accurate in in the true illustration of the power of an air gun. Most all your airgun manufacturers like to brag about high velocities in which they advertise and state muzzle velocity in feet per second or “FPS.” Canada and many other countries that restrict air gun ownership, base their restrictions on muzzle energy (i.e. Joules) and not strictly on FPS or velocity.
The common misunderstanding is that it is generally believed that an airgun producing a higher FPS equals greater knock down power. This is simply not true. If you compare a light alloy pellet, which is traveling at high velocities, with a larger, heaver pellet, traveling at a slower velocity, they will have completely different levels of knockdown power. In most cases the heaver pellet, even though it is not traveling as fast as the lighter alloy pellet, will keep the energy (i.e. speed) at a greater distance because it has a tendency not to slow down as rapidly as the lighter pellet. You need the weight of the pellet and the Feet Per Second (FPS) to calculate Foot Pounds of Energy (FPE). Especially for hunting and pest control, you need to find that pellet that gives you the most accuracy along with the Highest FPE. A chronograph is your friend in trying to determine that perfect pellet. I could list the formula but in this day in age as long as you have the pellet weight and FPS you can access a free calculator on the internet or for that matter there are chronographs that provide that information. In most all the reviews I do on pellet guns I will cover FPE.
The foot-pound is a unit of measurement of energy (FPE). One foot-pound (1 ft-lb) is defined as amount of energy expanded, or work done, while applying force of one pound-force (1 lb) to move an object for distance of one foot (1 ft). Keep in mind, under the proper conditions, a pellet gun (3.5 – 6 FPE) could be lethal, but I would recommend not hunting, depending on the size of game, with any airgun with less than 15 FPE.
Just to sum this up, remember FPS is not the solo determination of what makes the most powerful pellet gun.