Bullet Kinetic Energy Calculator
Calculate bullet kinetic energy in ft-lbs and Joules from velocity and bullet weight.
Used in sport shooting, ballistic analysis, and physics study.
Bullet kinetic energy is the usual first screen for whether a cartridge suits a given animal. It is not the whole story of terminal performance, but it is the number every hunting guideline is written in, so it is where the conversation starts.
Kinetic energy formula: KE = 0.5 × m × v²
In hunting units: KE (ft-lbs) = (bullet weight in grains × velocity in fps²) / 450,437
Or in metric: KE (Joules) = 0.5 × mass (kg) × velocity (m/s)²
Minimum recommended energies for ethical hunting (ft-lbs):
- Small game (rabbit, squirrel): 100–300 ft-lbs
- Medium game (deer, antelope): 1,000–1,500 ft-lbs
- Large game (elk, moose): 1,500–2,500 ft-lbs
- Dangerous game (bear, buffalo): 3,000+ ft-lbs
Common calibers and typical muzzle energy:
| Caliber | Typical Muzzle Energy |
|---|---|
| .22 LR | 100–140 ft-lbs |
| .223 Rem / 5.56 NATO | 1,200–1,400 ft-lbs |
| .308 Win / 7.62 NATO | 2,400–2,800 ft-lbs |
| .30-06 Springfield | 2,700–3,100 ft-lbs |
| .300 Win Mag | 3,400–3,800 ft-lbs |
| .338 Lapua | 4,500–5,000 ft-lbs |
| .375 H&H (dangerous game) | 4,300–4,800 ft-lbs |
Energy at distance: the number this page gives you is muzzle energy, and that is not what reaches the animal. A .308 Win leaving at about 2,600 ft-lbs is down to roughly 1,250 to 1,700 ft-lbs at 300 m depending on the bullet. That still clears the deer threshold, but it sits at the bottom edge of what people ask of a .308 for elk. Always check the energy at the distance you actually intend to shoot.
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This calculator runs entirely in your browser, so the numbers you enter stay on your device. The math behind it is written by hand and tested against worked examples and standard references before the page goes live.
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