Arrow Speed Calculator

Estimate arrow speed from bow IBO rating and setup.

Bow IBO speed (fps)

Draw length

Draw weight

Arrow weight (gr)

Estimated speed (fps) 283.33

Formula: ≈ IBO + 10·(DL−30) + 2·(DW−70) − (gr−350)/3

Step-by-step with your numbers:

1. Values used:

2. Bow IBO speed = 320 fps

3. Draw length = 29

4. Draw weight = 65

5. Arrow weight = 400 gr

7. Estimated speed = 283.33fps

Did we solve your problem today?

Estimate how fast a compound bow shoots an arrow, adjusting the IBO rating for your setup.

The math behind it

Start from the IBO speed (rated at 30", 70 lb, 350 gr): add ~10 fps per inch of draw, ~2 fps per pound, and subtract ~1 fps per 3 grains over 350.

320 IBO, 29" draw, 65 lb, 400 gr → about 283 fps.

How accurate is it?

An estimate — real speed varies with bow efficiency; chronograph for exact values.