I’ve watched too many hunters blame their broadheads for poor arrow flight when the real problem was sitting right there in their FOC percentage. Front of center isn’t some fancy archery term you can ignore. It’s the difference between arrows that fly like darts and arrows that wobble downrange like a drunk bee.
Use our FOC calculator below to figure out where your arrow’s weight is sitting. Takes two measurements and 30 seconds.
What Is FOC and Why Should You Care?
F.O.C. (front of center) is the percentage of your arrow’s weight that sits forward of the center point. You measure it by finding your arrow’s balance point, comparing it to the center of the arrow, then running a quick calculation.
The formula looks like this:
- Take the arrow and balance it on something.
- Measure from the throat of the nock to that balance point.
- Then measure your total arrow length from the nock throat to the end of the shaft (don’t include the length of your point).
- The difference between your balance point and actual center, divided by total length, times 100 – that’s your FOC percentage.
Or just use our FOC calculator and skip the math.
🎯 FOC Calculator
How to Measure Your Arrow:
- Measure total arrow length from the throat of the nock to the end of the shaft (NOT including the point) in inches
- Balance your arrow on a rail or edge of a table
- Mark the balance point with a pencil
- Measure from the throat of the nock to that balance point in inches
FOC is the percentage of your arrow’s weight distributed forward of center. The formula is: ((Balance Point – (Arrow Length ÷ 2)) ÷ Arrow Length) × 100. Higher FOC means more weight up front, which improves penetration and arrow flight stability but may reduce speed slightly. Target shooters prefer 6-9%, while bowhunters typically run 10-15% for reliable performance on game.
How FOC Affects Arrow Performance
Higher FOC means more weight up front. That extra weight improves penetration and makes your arrow flight more stable. The arrow wants to fly point-first, which is exactly what you need when you’re trying to punch through hide, ribs, and whatever else is between you and a clean kill.
But there’s a trade-off. More weight up front means you’re sacrificing some velocity. Your arrow speed drops slightly, which affects trajectory at longer distances.
Target archers run lower FOC (6-9%) because they want maximum speed and the flattest possible flight path. Bowhunters typically aim for 10-15% FOC. That’s the sweet spot where you get reliable arrow flight and serious kinetic energy for ethical kills on game.
Building the Right Arrow Setup
When you’re putting together a hunting arrow, your broadhead choice matters more than you think for FOC. A 100-grain Rage Hypodermic adds less front weight than a 125-grain Muzzy Trocar. That 25-grain difference shifts your balance point forward.
Same goes for inserts. Heavy inserts and outserts are popular ways to increase FOC without changing your broadhead weight. You’re adding mass right at the front of the arrow shaft, which pushes that balance point exactly where you want it.
Carbon arrows make this easier to fine-tune than aluminum ever did. You can play with different components – nocks, vanes, inserts, broadheads – until your measurement is taken and you’re sitting in that ideal 10-15% range for bowhunting.
The Bottom Line on Arrow Balance
Perfect accuracy and maximum penetration both depend on getting your FOC calculation right. Too low and your arrows won’t fly consistent or penetrate well. Too high and you’re giving up speed you might need for longer shots.
Measure the distance from your nock throat to your balance point. Measure your total arrow length. Plug those numbers into the calculator. See where you land. If you’re outside that 10-15% hunting range, start adjusting components until you’re in the zone.
What’s your current setup running for FOC? Ever had an arrow that just wouldn’t fly right?
