1. What is FOC (Front of Center)?

FOC (Front of Center) is a measurement used in archery to describe the balance point of an arrow. It represents the percentage of the arrow's total weight that is located in the front half of the arrow.

2. How Does the Calculator Work?

The calculator uses the FOC formula:

Where:

• \( ArrowLength \) — Total length of the arrow (inches)
• \( CenterOfGravity \) — Balance point of the arrow measured from nock end (inches)

Explanation: The equation calculates what percentage of the arrow's weight is forward of the center point.

3. Importance of FOC Calculation

Details: Proper FOC affects arrow flight stability and accuracy. Higher FOC arrows tend to fly better but may sacrifice speed. Most target arrows have FOC between 7-15%, while hunting arrows typically have 10-20%.

4. Using the Calculator

Tips: Measure arrow length from nock groove to end of shaft (not including point). Measure center of gravity by balancing arrow on a narrow edge. Both values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What is the ideal FOC percentage?
A: Ideal FOC depends on arrow purpose. Target archers typically use 7-15%, while hunters prefer 10-20% for better penetration.

Q2: How does FOC affect arrow flight?
A: Higher FOC increases arrow stability but reduces speed. Lower FOC increases speed but may decrease accuracy at longer distances.

Q3: How can I adjust my arrow's FOC?
A: Add weight to point end (increase FOC) or nock end (decrease FOC). Changing point weight is the most common adjustment.

Q4: Does FOC affect broadhead flight?
A: Yes, broadheads typically require higher FOC (12-20%) for stable flight compared to field points.

Q5: Should I measure FOC with or without fletching?
A: Measure with all components installed (points, inserts, fletching, nocks) as you would shoot the arrow.