How to Improve Arrow FOC
Measure your arrow's front-of-center balance, calculate it with the FOC calculator, then adjust point or insert weight to fit your discipline and tuning goals.
Tools and supplies
Tools
- A ruler or tape measure (at least as long as your arrow)
- A fine-tip marker or masking tape
- A narrow balance point: a pencil, a thin dowel, or the edge of a table
Supplies
- Your assembled arrow (shaft, insert, point, nock, and fletching all installed)
Steps
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Assemble the arrow exactly as you shoot it
Measure FOC with the arrow fully assembled: nock, fletching, insert, and point all in place. Any component you leave off changes the result. If you are comparing different point weights, assemble one complete arrow for each weight you want to test.
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Mark the exact center of the arrow
Measure the total length of the arrow from the bottom of the nock groove to the end of the shaft, not including the point. Divide by two, then mark that midpoint with a fine-tip marker or a strip of masking tape.
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Find the balance point
Balance the arrow on something narrow and consistent. A pencil works well. Slide the arrow back and forth until it rests level without tipping, then mark that spot.
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Measure from center to balance point
Measure from the center mark you made in step 2 to the balance point you just found. That number is how far forward of center the arrow balances.
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Calculate FOC
Divide that forward distance by the total arrow length, then multiply by 100. That gives you a percentage: your FOC. If you would rather skip the arithmetic, put both measurements into the FOC Calculator at /tools/foc-calculator/ and it does the math for you.
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Read the number in context
There is no single correct FOC. Lower percentages favor speed and flatter trajectory, which suits target archery where distance is fixed and penetration is not the goal. Higher FOC improves stability at long range and puts more energy into penetration on impact, but the arrow drops more and flies slower. Where your setup should land depends on what you actually shoot and at what distances.
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Adjust point or insert weight to shift FOC
A heavier point shifts balance forward and raises FOC; a lighter one brings it back. Heavier inserts do the same thing in smaller increments. Adding weight up front costs arrow speed, so every gain in FOC trades against something. Change one component, remeasure, and recalculate before making another move.
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Re-tune after any FOC change
Point or insert weight changes how the arrow reacts off the bow. After any meaningful FOC shift, paper tune or bare-shaft tune again to check arrow flight, and re-check your sight marks. Heavier points fly on a different arc than lighter ones.
Measuring and tuning front-of-center
Front-of-center (FOC) is a percentage: how far forward of the arrow’s geometric center the balance point sits. Nose-heavy arrows have high FOC. Arrows that balance closer to the middle have lower FOC.
It matters because it affects how the arrow self-corrects in flight, how stable it is at distance, and how much energy it carries into a target on impact. Measure it when building a new setup or swapping point weights. Revisit it if you change disciplines — a hunting setup often runs higher FOC than a target setup, sometimes by several percentage points, because the priorities are different.
If your arrows are already grouping well, you may not need to change anything. Good groups at your normal distances are the real test; FOC helps you understand why an arrow setup behaves the way it does. Put your measurements into the FOC Calculator and let it run the numbers. If you are not sure what to do with the result, bring your setup in: a Point Blank Archery coach can look at the whole picture, including spine, point weight, and how the bow is currently tuned.