Arrow front of center (FOC) can be an important concept for the target archer and bowhunter. Having a proper FOC will help increase arrow stability, accuracy and penetration. For more detailed information on arrow FOC, please see the
Arrow FOC Basics article

Enter the total length “L”:

Enter the measured length “B”:

FOC = %

AMO, Method 1 (Recommended):
1) Measure the length of the arrow shaft from the throat of the nock to the end of the shaft, excluding the insert, this is “L
2) Using a sharp edge, balance the arrow (including the point, fletchings and nock) and mark the balance point
3) Measure the distance from the throat of the nock to the balance point, this is “B

Method 2:
This method replaces the total length of the arrow, including the point, for the “L” value.

FOC Diagram