How to Calculate FOC on an Arrow
FOC (front of center) is the percentage that describes how far forward the arrow balances relative to the center of the shaft.
FOC Formula
FOC = ((balance point - arrow length / 2) / arrow length) x 100
Measurement Steps
- Measure arrow length from nock throat to the back of the point.
- Find the balance point and measure from nock throat.
- Apply the values to the formula or use the calculator.
Use the FOC calculator to validate your numbers quickly.
Calculate Foc
This page applies front of center (FOC) principles using arrow balance point, nock groove measurement, arrow shaft length, and component weight values such as insert weight, broadhead weight, and GPI. For practical tuning, use measured FOC percentage with dynamic spine checks and broadhead flight validation.
External Standards and Data Sources
- ATA IBO speed rating standard references
- Easton Archery arrow selection and spine resources
- Gold Tip official GPI and component specifications
- Victory Archery spine chart and arrow model data
Internal Links for Next Steps
- FOC calculator
- arrow weight and FOC calculator
- how to calculate FOC
- FOC arrow build guide
- arrow FOC calculator
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