PC Archery includes an Arrow Energy-Speed Calculator that you can use to calculate your arrow's energy or to see the effect changing arrows would have on your arrow speed.

The Energy-Speed Calculator takes Arrow Speed and Arrow Weight as inputs and calculates your Arrow Energy. You can also "fix" your arrows energy and then change the arrow weight to see the effect it would have on Arrow Speed.

Bow Speed Estimator
The Bow Setup Page estimates your arrow speed based on the values you enter for Eye to Sight Distance, Peep to Sight Distance and the gap between your 20 and 60 yard pins. When you enter the Energy-Speed Calculator screen this estimated speed is filled as the default value for speed. You can change this speed value by simply typing in a new value or by going back and changing your bow setup.

You can use your actual arrow weight or estimate it. If you select "Use estimated arrow weight" use the Arrow weight estimator (right side of the screen) to select a shaft, enter its length, specify tip weight, etc.