Arrow Speed Calculator
Estimate arrow speed from bow IBO rating and setup.
Estimate how fast a compound bow shoots an arrow, adjusting the IBO rating for your setup.
How the Math Works
The Arrow Speed Calculator uses a mathematical approximation to estimate arrow speed based on your bow's IBO rating and setup specifications. The formula accounts for variations in draw length (DL), draw weight (DW), and arrow grain (gr) by adjusting the base IBO value. Specifically, it adds 10 feet per second for each inch of draw length over 30 inches, adds 2 feet per second for each pound of draw weight over 70 pounds, and subtracts one-third of a foot per second for each grain over 350 grains. These adjustments help refine the base IBO rating to better match your specific bow and arrow configuration.
Practical Applications
To use this calculator, input your bow's IBO rating, your draw length in inches, draw weight in pounds, and the arrow grain weight. The formula automatically applies the adjustments: if your draw length is less than 30 inches, the speed decreases by 10 feet per second for each inch below; similarly, if your draw weight is under 70 pounds, it subtracts 2 feet per second per pound. For arrow grain, if your arrow weighs more than 350 grains, the speed decreases by one-third of a foot per second per grain over 350. This helps archers optimize their setup by predicting how changes in equipment will affect arrow velocity.
Day-to-Day Use
This tool helps archers make informed decisions when selecting equipment for hunting, competition, or practice. By estimating arrow speed, you can choose appropriate arrow weights for your bow to ensure safe and effective performance, avoiding risks like dry firing or using underspined arrows. It also aids in comparing different bow setups or understanding how upgrades (e.g., increasing draw weight) might impact arrow speed. Whether tuning for accuracy, selecting broadheads, or preparing for a hunt, knowing your arrow speed ensures better precision and safety in everyday archery activities.
Worked example
320 IBO, 29" draw, 65 lb, 400 gr → about 283 fps.
FAQ
How accurate is it?
An estimate — real speed varies with bow efficiency; chronograph for exact values.