Arrow Speed Estimator
Estimate arrow speed from a bow's IBO rating and your actual draw length, draw weight, and arrow weight. A rule-of-thumb estimate — a chronograph is always more accurate.
How this works
IBO (International Bowhunting Organization) speed ratings are measured under fixed lab conditions: 30" draw length, 70 lb draw weight, and a 5 grains-per-pound arrow. This calculator starts from that number and adjusts for how your actual setup differs on each of those three variables, using widely used rule-of-thumb adjustment rates.
Where this estimate can be off
Cam design, let-off, string and cable weight, and accessories (peep, silencers, a stabilizer) all shift real-world speed in ways this simple formula can't see. Treat the result as a planning number for arrow selection and sight-tape work — a chronograph reading of your actual bow and arrow combination is the only way to know your real speed.
Frequently asked questions
Why is my actual arrow speed usually slower than the IBO rating?
IBO ratings are measured under fixed lab conditions — a light 5 grains-per-pound arrow, 30" draw, 70 lb draw weight — which almost never matches a real hunting setup with a heavier arrow, broadhead, and accessories.
How much does draw length really change my speed?
Roughly 10 fps per inch of draw length difference from the 30" IBO reference is the widely used rule of thumb applied here, though real bows vary somewhat by cam design.
Is a chronograph really necessary if I use this calculator?
This gives a solid planning estimate, but only a chronograph reading of your actual bow and arrow combination tells you your real speed — cam design, accessories, and string condition all affect the result in ways this simple formula can't see.
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