Ammunition makers usually publish a bullet’s weight in grains and either its muzzle velocity or muzzle energy. Converting between them lets hunters and sport shooters compare loads and check that a round meets the minimum energy required for game.
How to use the Muzzle Velocity Calculator
- What do you know?
- Bullet mass
- Muzzle energy
- Muzzle velocity
Results update as you type, every field has its own unit menu, and everything is calculated in your browser.
How it works
Choose whether you know the energy or the velocity. Mass can be entered in grains or grams and energy in joules or foot-pounds.
Inputs explained
| Field | What to enter |
|---|---|
| What do you know? | Choose one: Kinetic energy and mass, Velocity and mass |
| Bullet mass | Units: gr, g, kg, oz |
| Muzzle energy | Units: ft·lbf, J, kJ |
| Muzzle velocity | Units: ft/s, m/s, mph, km/h |
What each result means
- Muzzle energy = [Bullet mass]×[Muzzle velocity]^2÷2
- Momentum = [Bullet mass]×[Muzzle velocity]
Example values
How the main result changes when Bullet mass changes and everything else stays at the example values above:
| Bullet mass (gr) | Muzzle velocity (ft/s) |
|---|---|
| 75 | 4,115.39 |
| 112.5 | 3,360.2 |
| 150 | 2,910.02 |
| 187.5 | 2,602.8 |
| 225 | 2,376.02 |
| 300 | 2,057.69 |
Formula
v = √(2E/m), E = ½mv²
Worked example
Inputs — What do you know?: Kinetic energy and mass; Bullet mass: 150 gr; Muzzle energy: 2,820 ft·lbf.
Results — Muzzle velocity = 2,910.02 ft/s; Muzzle energy = 2,820 ft·lbf; Momentum = 8.6212 kg·m/s.
Key terms
- Muzzle velocity
- The speed of the projectile as it leaves the barrel.
Frequently asked questions
What is a grain?
A unit of mass: 7,000 grains = 1 lb; 1 grain = 64.8 mg.
How fast is a typical rifle bullet?
Roughly 750–1,000 m/s (2,500–3,300 ft/s).
Does barrel length change muzzle velocity?
Yes – longer barrels usually give more speed, up to a point.
Why does energy grow faster than velocity?
Energy is proportional to the square of velocity.