Your bow
IBO is the bow’s rating. String weight is peep plus D-loop.
Kinetic Energy Calculator
Kinetic energy is how hard the arrow hits, in foot-pounds, from finished grains and speed. Drag the sliders to match your bow and arrow. The tiles update as you go. This calculator is free — no account. Confirm the speed with a chrono before you hunt.
2
Your arrow
Weigh the finished arrow, or take the grain estimate from the 3D custom arrow builder.
425 gr
40 yd
3
Results
- Arrow speed IBO estimate
- — fps
- Kinetic energy
- — ft-lbs · —
- Momentum
- — slug·ft/s
- GPP
- — grains / lb
- Time to target
- — at 40 yd, with drag
Compare
Tables use the IBO speed estimate, even if you typed a chrono number. Highlighted row is closest to your sliders.
| Grains | fps | KE | Momentum |
|---|
What the number means
Read the foot-pounds on the finished arrow you will hunt. Under about 40 ft-lbs is light for big game. 40–55 ft-lbs is the window most deer and elk hunters land in. Past about 65 ft-lbs is a heavy setup — more punch, more momentum, and usually more drop. Confirm the speed with a chrono before you trust the number.
GPP is grains per pound of draw weight. Under 8 is a light arrow. 8–12 is a typical hunting build. Past 12 is heavy.
Speed here is an IBO estimate unless you type a chrono number. Time to target uses drag, so a heavier arrow is slower downrange than a straight split. Check spine on the TitleX spine chart and front of center on the FOC calculator.
Related resources: arrow calculators, FOC calculator, arrow spine chart, arrow flight calculator, 3D custom arrow builder.