Sports

Arrow FOC Calculator

Find an arrow's front-of-center (FOC) balance percentage.

Arrow length

Balance point from nock

Calculated Output

FOC (%) 6.897

Formula: FOC = (balance − length/2) ÷ length × 100

Step-by-Step Breakdown

1. Values used:

2. Arrow length = 29

3. Balance point from nock = 16.5

5. FOC = 6.897%

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The math behind it

FOC = (balance point from nock − half the arrow length) ÷ arrow length × 100.

29" arrow balancing at 16.5" → about 6.9% FOC.

What FOC is ideal?

Roughly 7–15% for hunting; higher FOC improves penetration but lowers speed.