What is FOC in archery?

FOC in archery means front of center: the distance between an arrow's midpoint and its balance point, expressed as a percentage of arrow length. You calculate it from the finished arrow's length and balance point. Measure both from the throat of the nock, the groove where the bowstring seats.

What the percentage tells you

A 12% FOC arrow balances ahead of its midpoint by a distance equal to 12% of its measured length. That number does not mean 12% of the arrow's weight is in the point. Two arrows can have the same FOC and very different total weights.

Forward balance works with fletching to affect how an arrow settles in flight. Target arrows commonly sit around 7 to 15 percent; many hunters build higher. These are common practices, not equipment rules or guarantees of accuracy. A well-matched shaft and clean launch still matter.

How to measure and calculate FOC

  1. Assemble the complete arrow with the point, insert, nock, fletching, and any wrap you intend to shoot.
  2. Measure arrow length from the throat of the nock, where the string seats, to the end of the shaft. Exclude the projecting point.
  3. Balance the finished arrow on a narrow support. Mark that position and measure to it from the same nock reference.
  4. Subtract half the arrow length from the balance-point measurement. Divide the result by arrow length, then multiply by 100.

FOC % = (balance point - arrow length / 2) / arrow length x 100. Use the same units for both measurements. The arrow FOC calculator handles the arithmetic.

For example, a 30-inch arrow that balances 18 inches from the nock has its midpoint at 15 inches. Its balance point is 3 inches ahead of center, so FOC is 3 / 30 x 100 = 10%. The point stays installed while you balance it, even though its projecting length is excluded.

Changing balance without losing the tune

A heavier point or insert moves the balance point forward. More weight at the rear, such as a heavier nock or wrap, moves it back. Weigh and measure the finished build again after changing components; catalog weights alone cannot tell you exactly where it balances.

Adding point weight also increases how much the arrow bends during launch, often called a weaker dynamic spine. Check arrow spine before making a large change, then test arrow flight and groups. Record total arrow weight alongside FOC so you can separate a balance change from a weight change.

Questions

Is higher FOC always better?

No single FOC percentage suits every arrow and purpose. Increasing it by adding point weight also changes total weight, trajectory, and dynamic spine. Start with a shaft matched to your bow, then compare finished builds at the distances you shoot. Keep the setup that produces dependable flight and groups.

Do I measure FOC with the point installed?

Yes. Balance the arrow with every component installed, including the point. For the arrow-length part of the formula, measure only from the nock throat to the shaft end. Mixing those two instructions is a common source of incorrect results: the point contributes weight without adding to the specified length.

Can two arrows of the same weight have different FOC?

Yes. Total weight tells you how heavy an arrow is; FOC describes how that weight is distributed along its length. A heavier insert and lighter rear components can shift balance forward while keeping the total similar. Measure each finished build instead of assuming matching weights mean matching balance.