Arrow Speed Calculator
Enter your bow's IBO speed and setup details to find your real-world arrow speed, kinetic energy, and momentum.
Note: Speed estimate does not account for string accessories (peep sight, D-loop, string dampeners, nock sets). A good rule of thumb is roughly 1 FPS lost per 5 grains of weight added to the string.
Kinetic Energy & Momentum Calculator
Already know your arrow speed? Enter it here with your arrow weight to get KE and momentum.
Animal Reference Chart
Minimum recommended kinetic energy and momentum values for ethical hunting.
| Animal | Min Kinetic Energy | Min Momentum | |
|---|---|---|---|
| 🦃 | Turkey / Small Game | 25.0 ft-lbs | 0.25 slug-ft/s |
| 🦌 | Whitetail Deer | 42.0 ft-lbs | 0.4 slug-ft/s |
| 🐻 | Black Bear | 52.0 ft-lbs | 0.5 slug-ft/s |
| 🫎 | Elk / Moose | 60.0 ft-lbs | 0.55 slug-ft/s |
| 🦬 | African Plains Game | 70.0 ft-lbs | 0.65 slug-ft/s |
Frequently Asked Questions
What is IBO speed?
IBO speed is the speed rating assigned by the International Bowhunting Organization. It's measured at 70 lbs draw weight, 30 inch draw length, and a 350 grain arrow with no string accessories. Your real-world speed will be lower based on your actual setup.
How much speed do I lose per inch of draw length?
Approximately 10 FPS per inch below 30 inches. So if your draw length is 28 inches, expect to lose about 20 FPS from the IBO rating.
What matters more — kinetic energy or momentum?
Kinetic energy measures the total energy delivered on impact, while momentum measures penetration potential. Many experienced hunters trust momentum more for predicting penetration, especially on heavy-boned animals. Ideally you want both numbers above the minimum for your target animal.
How much speed do I lose for arrow weight?
Roughly 1.5 FPS for every 5 grains over the 350 grain IBO standard. A 450 grain arrow would cost you about 30 FPS compared to IBO.
What is a good arrow weight for hunting?
The general rule is a minimum of 5 grains per pound of draw weight. At 70 lbs, that's 350 grains minimum. Most serious hunters shoot 400-500 grains for whitetail and 450-600+ grains for elk. Heavier arrows penetrate better but fly slower with more arc.