How to Calculate FOC on an Arrow

FOC (front of center) is the percentage that describes how far forward the arrow balances relative to the center of the shaft.

FOC Formula

FOC = ((balance point - arrow length / 2) / arrow length) x 100

Measurement Steps

1. Measure arrow length from nock throat to the back of the point.
2. Find the balance point and measure from nock throat.
3. Apply the values to the formula or use the calculator.

Use the FOC calculator to validate your numbers quickly.