Front of Center (FOC) is the percentage of an arrow's total length that sits in front of the physical center point. A higher FOC means more weight up front, which improves stability, penetration, and flight consistency — especially at hunting distances.
The NFAA-recommended hunting range is 10–15%. Many big-game hunters push toward 15–25% for maximum penetration on tough animals.
Measure from the throat of the nock (where the string seats) to the balance point. The balance point is where the arrow rests perfectly on a single finger.