Traditional arrow build: 8.15% FOC
A 125 grain point on a 11.0 GPI, 30 inch shaft gives 8.15% FOC (normal foc) and a total arrow weight of 500 grains. Adjust any component to see the effect.
A 125 grain point on a 30 inch shaft at 11.0 GPI balances 17.45 inches from the nock throat, giving 8.15% front of center — normal foc — at a total arrow weight of 500 grains. Full-length shaft with feathers: heavier at the back, so FOC lands lower.
Arrow build
Component weights in grains; shaft weight comes from GPI × length.
For grains per pound
Normal FOC — The range most factory arrows land in. A good all-round balance of trajectory and stability.
How this was calculated
Arrow weight
- Shaft: 330.0 gr
- Front end (point + insert + collar): 125.0 gr
- Back end (nock + fletching + wrap): 45.0 gr
- Total: 500.0 grains
- 8.33 grains per pound of draw weight
The balance point is estimated by treating the shaft as a uniform rod. Weigh and balance the finished arrow for an exact figure.
What the number means
| FOC range | Description |
|---|---|
| under 7% | Low FOC — Flatter trajectory but less forgiving in flight. Common on target setups shooting light points. |
| 7–10% | Normal FOC — The range most factory arrows land in. A good all-round balance of trajectory and stability. |
| 10–15% | High FOC — Popular for hunting: better arrow flight stability and forgiveness, with only a modest drop in trajectory. |
| 15–19% | Extreme FOC — Ashby-style setup. Strong penetration and stability; expect a noticeably more arcing trajectory past 30 yards. |
| 19%+ | Ultra-extreme FOC — Maximum penetration territory. Trajectory drops off quickly, and arrow tuning gets fussy. |
This build in numbers
| Shaft length | 30 in |
| Shaft GPI | 11.0 grains per inch |
| Shaft weight | 330 gr |
| Point | 125 gr |
| Insert | 0 gr |
| Nock | 10 gr |
| Fletching | 35 gr |
| Total arrow weight | 500 gr |
| Balance point | 17.45 in from the nock throat |
| Front of center | 8.15% (Normal FOC) |
| Grains per pound | 11.11 gpp at 45 lb |
The range most factory arrows land in. A good all-round balance of trajectory and stability.
Compare other builds
Frequently asked questions
What FOC does a 125 grain point give? ▾
On this build — a 30 inch shaft at 11.0 GPI with a 0 grain insert, 10 grain nock and 35 grains of fletching — a 125 grain point gives 8.15% FOC, which counts as normal foc. Change any component in the calculator to see how the number moves.
How much does this arrow weigh? ▾
About 500 grains in total: 330 grains of shaft, 125 grains up front, and 45 grains at the back. At 45 lb of draw weight that is 11.11 grains per pound.
Is 8.15% a good FOC? ▾
Normal FOC. The range most factory arrows land in. A good all-round balance of trajectory and stability.
Will this estimate match my measured FOC? ▾
It should be close. The estimate treats the shaft as a uniform rod and puts the front components right at the tip, so a build with a long outsert or an unusual shaft taper can differ by a few tenths of a percent. Balance the finished arrow for the exact figure.
About this Calculator
A 125 grain point on a 11.0 GPI, 30 inch shaft gives 8.15% FOC (normal foc) and a total arrow weight of 500 grains. Adjust any component to see the effect.