The Arrow FOC Calculator

Arrow FOC Calculator (How to Measure & Calculate FOC)

Want to see how to measure and calculate arrow FOC? The Arrow Forward of Center calculation (sometimes referred to as Front of Center calculation) is one of the most discussed features of arrow tuning and setup these days and for good reason.

FOC plays a critical role in the flight of an arrow and its overall penetration capability. Archery hunters want an arrow that flies right and hits the animal they are hunting hard and true. An arrow with the right FOC can provide this in spades. The Arrow FOC Calculator below will make this easy to figure out.

*If you don’t know how to use the calculator below, see the How to Measure FOC instructions and graphic under the calculator.

The FOC Calculator Diagram

How Do You Measure FOC?

If you don’t know how to use the calculator above already, FOC is calculated by getting two key measurements. First, find where you can balance the arrow using a pen, pencil, nail, or something similar. Mark this “Balance Point” on your arrow. Then take the following steps and take all measurements in inches.

  1. Measure from the throat of the nock to the Point of Balance. This is your Point of Balance (POB) measurement.
  2. Then measure from the back of your field point to the throat of the knock. This is your Total Length (TL) measurement.
  3. Then divide the total length measurement by 2. This gives you half of the TL measurement. (.5TL)
  4. Then subtract half the total length measurement from the point of balance measurement. (POB – .5TL)
  5. Then multiply the result of Step 4 by 100.
  6. Then divide the result of Step 5 by the TL found in Step 2.

The example below follows the exact steps listed above:

  1. POB – 18 inches
  2. TL – 27.5 inches
  3. 27.5 / 2 = 13.75
  4. 18 – 13.75 = 4.25
  5. 4.25 x 100 = 425
  6. 425 / 27.5 = 15.45% FOC

Arrow FOC is measured as the percentage of weight that is in the front end of your arrow. It is determined based on the balance point of your arrow and the percentage of distance the balance point is from the back of the field point or broadhead. It is recommended to use field points and not broadheads when measuring your arrows.

The FOC calculator here will allow you to test your arrows and see if they fit the percentage of FOC you are trying to achieve. To get the full picture of how capable your arrows are, it is also important to understand their speed, kinetic energy, and momentum. It all matters when trying to create the perfect arrow set up for your bow.

Calculate your arrow’s FOC percentage in just two steps using the calculator above. Make sure you take your measurements using the guidelines in the graphic above too.

What is the Best FOC for My Arrows?

The best FOC percentage for arrows depends on the type of archery activity you are doing. The forward-of-center percentage for arrows and its application to your archery event makes a difference. Here are a few common recommendations for different archery activities from some of the top arrow vendors in the USA.

  • FITA (Olympic Style) – 11% to 16%
  • 3-D Archery – 6% to 12%
  • Field Archery – 10% to 15%
  • Bow Hunting – 10% to 15%
  • High FOC Hunting Arrows – 15 to 30%

What are High FOC Arrows?

High FOC arrows are growing in popularity with Bow Hunters because they are extremely effective at improving their accuracy and lethality. A high FOC helps arrows fly straighter and it improves the ability of fletchings to steer the arrow to its intended target. A high FOC arrow is normally considered any arrow that is over 15%.

Some hunters have adopted strategies that include using extremely light carbon arrows coupled with high-weight inserts and broadheads to achieve upwards of 25- 30% in some cases. This is because high FOC, coupled with the right broadhead, can increase penetration on an animal by focusing the energy of the shot to the front of the arrow, assist in passing through bone and other obstacles, and ensure animals fall dead within seconds versus minutes or hours.

*Remember, optimizing your arrows begins at the time of purchase. Learn how to buy arrows the right way and you will optimize your arrow-tuning process.

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