How to Find an Arrow's Kinetic Energy

Kinetic energy is a measure of how much power a moving object has and how hard it will hit. An arrow's kinetic energy is the primary indicator of how much penetration the arrow will have; more kinetic energy will mean greater penetration. Factors such as arrow construction and arrow head type also impact penetration, but to a much lesser extent than its kinetic energy. Calculate the kinetic energy of your arrows to be confident that they will have the hitting power you need.

Things You'll Need

  • Measuring tape
  • Bow with sight
  • Arrow
  • Archery range
  • Calculator
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Instructions

  1. Arrow Velocity

    • 1

      Measure the distance, in centimeters, from your eye to the sight pin of your bow when holding it as you would to draw, using a measuring tape.

    • 2

      Got to an archery range and shoot the arrow at different differences. Note the distances in meters.

    • 3

      Measure the change in your sight mark setting between the two distances.

    • 4

      Navigate your browser to the Arrow Speed Calculator. Plug distances and change in sight mark setting into the appropriate field and click the “OK” button to get your arrow's velocity in fps.

    Calculate Kinetic Energy

    • 5

      Find your arrow's total weight in grains. This is listed in arrow description. Remember to adjust if you have changed the arrow head. Alternatively, you can weigh the arrow yourself.

    • 6

      Plug the velocity in fps from section one and arrow weight in grain into the equation for kinetic energy.

      Kinetic Energy = arrow weight x velocity squared ÷ 450,240

    • 7

      Solve the equation to get the Kinetic Energy of your arrow in foot-pounds using your calculator.