arrow customization
Archery F.O.C. Calculator
F.O.C. stands for Front of Center balance point. This measurement results from the relative weights of the components of your arrow (insert, point, fletching and nock). A properly balanced arrow measurement is 7%–15%.
Enter required information below to calculate your finished arrow weight and F.O.C.
Throat of the nock to the end of the shaft. Do not include the point.
Balance the fletched arrow with nock and point installed, then measure from the throat of the nock.
Balance point can't be longer than the arrow. Check your measurements.
F.O.C. = 100 × (B − A/2) ÷ A
A is arrow length, B is the balance point measured from the throat of the nock. The result is a percentage, so inches and centimeters give the same answer.
How to Measure F.O.C.
Measure Arrow Length (A)
Measure the overall length of the arrow from the throat of the nock to the end of the shaft. Leave the point out of this measurement.
Measure the Balance Point (B)
Build the arrow complete with nock, insert, point and fletching. Rest it across a straight edge or your finger until it balances. Mark that spot and measure back to the throat of the nock.
Calculate Your FOC
Enter your arrow length and balance point measurements into our F.O.C. Calculator above for a quick result. If you prefer to calculate it manually, use the formula below.
F.O.C. Formula
F.O.C. (%) = 100 × (B − (A ÷ 2)) ÷ A
what front of center means
Every arrow has a midpoint and a balance point. On a finished arrow those two rarely sit in the same place, because the point, insert and collar weigh more than the nock and vanes. F.O.C. is the distance between them, stated as a percentage of the arrow's length.
A higher number means more of the arrow's mass is carried up front. A lower number means weight is spread more evenly down the shaft.
why it matters
Flight Recovery
A front-loaded arrow straightens out of the bow faster and settles sooner.
trajectory
Pushing F.O.C. too high costs speed and drops your arrow faster at distance.
penetration
Mass concentrated behind the point drives energy into the target more efficiently.
wind resistance
Higher F.O.C. setups generally hold their line better in a crosswind.
Where you want to land
These are starting points, not rules. Draw length, point weight, spine and intended game all shift where your best setup sits. Build it, shoot it, and let groups decide.
7–11%
TARGET & 3D
11–15%
BOWHUNTING
15%+
HEAVY FRONT-LOAD BUILDS
What changes your number
Point & Insert Weight
The fastest lever you have. Moving from a 100 grain to a 125 grain point, or adding a brass insert, pulls the balance point forward and raises F.O.C.
arrow length
Cutting the shaft shorter moves the balance point closer to the front relative to overall length, so a shorter arrow usually reads higher.
shaft construction
Spine and wall thickness change how mass is distributed down the shaft, which shifts where the arrow balances before you add any components.
Nock & Vanes
Lighted nocks, wraps and larger vanes all add weight behind the midpoint and pull your F.O.C. down.
Build it, then check it
F.O.C. is one number in a bigger picture. Total arrow weight, spine match and point weight all work together, so change one component at a time, re-balance the arrow, and run the numbers again before you head to the range.
Tim Gillingham on F.O.C. and FACT
Team Gold Tip's Tim Gillingham breaks down what Front of Center actually does to an arrow and walks through worked examples using the FACT weight system.