Arrow FOC Calculator

FOC is the distance from the physical center to the balance point, divided by total arrow length, times 100. The physical center is half the arrow length, so a 29 inch arrow balancing at 16.5 in gives ((16.5 - 14.5) / 29) x 100 = 6.90 percent.

Most bowhunters aim for a front of center between 10 and 15 percent. That range tends to balance penetration and forgiveness while keeping the arrow flying true through the full distance.

Measure from the throat of the nock, the deepest point where the string sits, to the spot where the arrow balances on a thin edge. Use that same reference point for the arrow length.

Yes. If the balance point sits behind the physical center the FOC is negative, which means the arrow is tail heavy. This tool reports the negative value so you can rebalance with point or insert weight.

Add weight toward the front with a heavier field point or broadhead, brass inserts, or weighted collars. Lighter nocks and shorter fletching also shift the balance point forward and raise FOC.