FOC calculator
Enter your arrow length and its balance point and this returns front-of-center, the share of an arrow's weight carried in its front half. FOC trades a little trajectory for stability, and Easton's hunting range is a guide rather than a rule. The hunting-arrows guide covers spine and weight, the other two arrow numbers.
Measure the arrow length from the throat of the nock groove to the end of the shaft, not counting the point. Balance the finished arrow on an edge, mark where it sits level, and measure that balance point from the same nock throat.
Enter an arrow length (20 to 36 inches) and a balance point that falls within it to see FOC.
About this formula
Front-of-center follows Easton Archery's method. Take the balance point measured from the nock throat, subtract half the arrow length, divide by the arrow length, and multiply by 100. Easton recommends 10 to 15 percent for hunting setups.
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