Must be a number between 250 and 750.

Must be a number between 100 and 450.

Why Kinetic Energy Matters

Think of kinetic energy (KE) as the hammer and your arrow as the nail. KE does the work, driving broadheads through hide, muscle and bone. While most bowhunters pay an awful lot of attention to arrow speed, it’s only one part of the KE equation. Kinetic energy is impacted not just by arrow speed, but by arrow weight as well.

But, how fast is fast enough? How heavy is heavy enough? That's the fun in this game. Use our KE calculator to help with the task.

Why Momentum Matters

KE and momentum are easily confused and often interchanged. Both involve calculations of mass and weight, but in different ways. To simplify, bowhunters can think of momentum as energy retention—or penetration potential—downrange. Another way to look at it yet is what’s required to stop an arrow at a given distance.

Roughly speaking, momentum favors heavier projectiles while KE favors speed. The key is finding the sweet spot. You can go to a lighter arrow to increase your speed and probably get a KE boost. But that might actually reduce your momentum value—and the depth to which your arrow and broadhead will penetrate on a big bull elk.

Look at it this way: would it be easier to stop a finishing nail at 400 fps or a railroad spike at 300 fps?

Again, the Realtree Calculator will do the math for you. Have fun.