Forward of Center (FOC) Calculator

Formula

The formula to calculate the Forward of Center (FOC) is:

\[ \text{FOC} = \left(\frac{A + L}{2L}\right) \times 100 \]

Where:

FOC is the Forward of Center (%)
A is the distance from the nock groove to the finished arrow balance position (inches)
L is the arrow length (inches)

What is Forward of Center (FOC)?

To calculate the forward of center, sum the distance from the nock groove to the finished balanced position and the arrow length, divide the result by 2 and the arrow length, then multiply by 100. The FOC indicates the percentage of the arrow's length that the center of balance is located forward of the center point of the arrow.

Example Problems

Example 1:

Distance from Nock Groove to Balance Position (A): 13 inches
Arrow Length (L): 30 inches

Step 1: Calculate the FOC:

\[ \text{FOC} = \left(\frac{13 + 30}{2 \times 30}\right) \times 100 = 71.67\% \]

Therefore, the FOC is 71.67%.

Example 2:

Distance from Nock Groove to Balance Position (A): 15 inches
Arrow Length (L): 28 inches

Step 1: Calculate the FOC:

\[ \text{FOC} = \left(\frac{15 + 28}{2 \times 28}\right) \times 100 = 76.79\% \]

Therefore, the FOC is 76.79%.