Archery FOC Calculator

Archery FOC Image by István Kis

What is FOC and does it really matter?

Arrow FOC (front-of-center) is an important aspect to consider when selecting an arrow for archery. It refers to the balance point of the arrow and is expressed as a percentage of the arrow’s length from the front end. The FOC measurement determines how much weight is concentrated towards the front of the arrow compared to the back.

In general, a higher FOC indicates that the arrow is more front-heavy, while a lower FOC means the arrow is more back-heavy. The FOC can impact the stability, accuracy, and penetration of the arrow in flight. Arrows with a high FOC tend to have a flatter trajectory and better accuracy but may have decreased penetration. On the other hand, arrows with a lower FOC tend to penetrate more easily, but may not be as accurate due to their more unstable flight path.

Whether or not FOC really matters depends on the individual archer’s shooting style and preferences. Some archers find that a higher FOC works better for their shooting style and results in better accuracy, while others prefer a lower FOC for increased penetration. The type of bow being used, the type of arrow rest, and the type of bowstring also play a role in determining the ideal FOC for a particular setup.

In conclusion, arrow FOC is an important factor to consider when selecting an arrow for archery. It can affect the arrow’s stability, accuracy, and penetration, so it’s important to choose an arrow with the right FOC for your shooting style and preferences.

Arrow FOC Percentage Ranges:

Normal FOC: Usually ranges from 7% to 12%
Provides a good balance between stability and penetration
Suitable for most archers and shooting styles
High FOC: Ranges from 12% to 15%
Results in a flatter trajectory and increased accuracy
It may have decreased penetration
Extreme FOC: Ranges from 15% to 20%
Offers maximum accuracy and flatter trajectory
This may result in reduced penetration and increased arrow oscillation
Ultra Extreme FOC: Above 20%
Extremely front-heavy, may result in unstable arrow flight
Suitable only for experienced archers with specialized setups and shooting styles.

How to measure FOC

To measure the FOC of an arrow, you can follow these steps:

Gather materials: You will need a scale, an arrow, a marker, and a ruler.
Determine arrow length: Measure the total length of the arrow from the tip to the end of the nock groove.
Mark balance point: Hold the arrow at its midpoint and use the marker to make a small mark on the side of the arrow.
Measure distance to FOC: Place the arrow on the scale and measure the distance from the marked balance point to the front end of the arrow.
Calculate FOC: Divide the distance to the FOC by the total length of the arrow and multiply by 100 to get the FOC as a percentage.

For example, if the total length of an arrow is 30 inches and the distance to the FOC is 4 inches, the FOC would be (4/30)*100 = 13.3%

Note: The FOC can be influenced by the weight and distribution of the components used in an arrow (e.g., nocks, vanes, inserts, points, etc.), so it’s important to measure the FOC of each individual arrow to ensure consistency.