Muzzle Velocity & Energy Calculator
Convert bullet weight and muzzle velocity into muzzle energy in both ft-lbf and Joules for ammunition comparison and legal compliance checks.
Results
What is it?
Muzzle energy is the kinetic energy of a bullet at the moment it leaves the barrel, calculated as KE = �mv�. It is the most widely used single-number comparison metric for ammunition effectiveness and is also used in many jurisdictions to define legal minimum energy for hunting specific game.
How to use
Enter the bullet weight in grains (from the ammunition box) and the muzzle velocity in fps (also from the box or measured with a chronograph). The calculator converts to both ft-lbf (US standard) and Joules (metric/EU standard) instantly.
Example scenario
9mm 124-grain FMJ at 1,150 fps produces about 364 ft-lbf (494 J). A .45 ACP 230-grain at 830 fps delivers about 352 ft-lbf (477 J) � similar energy figures but delivered differently due to the velocity/mass tradeoff.
Pro tip
Many European countries require a minimum of 2,000 J (1,476 ft-lbf) for deer hunting. In the US, common minimums are 1,000�1,500 ft-lbf for deer and 2,500 ft-lbf for elk. Always verify local hunting regulations. Muzzle energy alone does not determine terminal performance � bullet construction is equally important.