Arrow Speed Calculator
Calculate the speed of an arrow based on bow draw weight, draw length, arrow weight, and bow efficiency. Get the arrow speed in feet per second (fps) and meters per second (m/s).
Published by:
isCalculator Editorial Team
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How to use this tool?
How to Use the Arrow Speed Calculator
This calculator estimates the speed of an arrow based on your bow setup. Follow these steps:
- Enter Draw Weight (lbs) – The force required to pull the bowstring to full draw (e.g., 70).
- Enter Draw Length (inches) – The distance from the bowstring at rest to full draw (e.g., 28).
- Enter Arrow Weight (grains) – The total weight of your arrow (e.g., 400). Use grains only.
- Enter Bow Efficiency (%) – A percentage (1–100) representing how well your bow transfers energy (e.g., 85).
- Click "Calculate" – The result shows arrow speed in feet per second (fps) and meters per second (m/s).
Note: All inputs must be positive numbers. Efficiency must be between 1 and 100. Use imperial units (lbs, inches, grains).
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Frequently Asked Questions
The calculator uses the formula: Speed (fps) = sqrt( (2 * (Draw Weight * Draw Length / 24 * Efficiency/100) * 32.174) / (Arrow Weight / 7000) ). This is derived from the kinetic energy stored in the bow and the mass of the arrow.
Draw weight is in pounds (lbs), draw length in inches, arrow weight in grains, and efficiency as a percentage.
Bow efficiency accounts for energy losses due to friction, string stretch, and other factors. A typical modern compound bow has an efficiency of 80-90%.
