1. What Is FOC (Front Of Center)?

FOC (Front Of Center) is a measurement that indicates the balance point of an arrow relative to its center. 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:

• \( Balance\;Point \) — Distance from nock end to balance point (inches)
• \( Center \) — Distance from nock end to center of arrow (inches)
• \( Arrow\;Length \) — Total length of the arrow (inches)

Explanation: The formula calculates the percentage difference between the actual balance point and the geometric center of the arrow.

3. Importance Of FOC Calculation

Details: Proper FOC is crucial for arrow flight stability, accuracy, and penetration. Higher FOC arrows typically fly better and penetrate deeper, while lower FOC arrows may be less stable but faster.

4. Using The Calculator

Tips: Measure all values in inches. Balance point is where the arrow balances perfectly. Center is exactly half the arrow length. All values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What is the ideal FOC percentage?
A: For compound bows, ideal FOC typically ranges from 10% to 15%. Target archers may prefer 10-12%, while hunters often prefer 12-15% for better penetration.

Q2: How do I measure balance point accurately?
A: Use a narrow edge (like a pencil or specialized arrow balance tool) and find the point where the arrow balances perfectly without tipping.

Q3: Can FOC be too high?
A: Yes, excessively high FOC (above 20%) can make arrows unstable and difficult to tune, while very low FOC (below 7%) may cause poor arrow flight.

Q4: How can I adjust FOC?
A: Add weight to the front (heavier points, inserts) to increase FOC, or add weight to the rear (heavier nocks, wraps) to decrease FOC.

Q5: Does arrow length affect FOC?
A: Yes, longer arrows generally have lower FOC with the same components, while shorter arrows tend to have higher FOC percentages.