What Is FOC And How To Calculate It

Dec 27, 2021Advanced Archery, Bow Tuning and Repair

If you’re new to archery, you may have heard the term F.O.C. and you may be wondering, what is F.O.C.? F.O.C. stands for “Front of Center”, an important aspect of proper arrow flight. The longer an arrow is in flight, the more important FOC proportions become. It really comes down to a matter of proper balance, as arrow balance directly affects your accuracy.

Since FOC affects the flight of your arrows, you must not only understand what FOC is, but why FOC is important, how to calculate your FOC, how to adjust your FOC, and how to determine what your arrow’s FOC should be.

Additional archery acronyms you must come to know when learning archery include DL (Draw Length), DW (Draw Weight), NP (Nocking Point), BH (Brace Height), and TD (Take Down).

What Is F.O.C.?

FOC refers to the balance of an arrow. Specifically, it indicates the percentage of the total weight of the front half of the arrow. FOC is calculated as a percentage of the total weight of an arrow and tells you how much of an arrow’s total weight is included in the front half of the arrow aka “front of center”. Front of center is one of the more essential elements that affect the shape of your arrow’s trajectory curve, making it necessary for you to figure out the correct balance position of your arrows.

While it would seem to make sense that an arrow’s center of mass should be located in its center to provide shooters with the most balanced shots, an arrow’s center of mass is actually located a little more towards the front of the arrow.

If your front of center is too heavy, which means it’s at too high of a percentage, it’ll drop faster. When your front of center is too heavy, your arrow will drop quickly and shorten your range. If your front of center is too light, arrow flight will have a less pronounced trajectory, meaning it will shoot flatter. While this is good for distance, it can create flight issues. This is because weight is more centered and the arrow is more easily affected by user error and weather conditions. Arrows perform best when there is slightly more weight towards the tip and fletching to correct any inconsistencies.

FOC For Target Shooting

Calculating FOC for target shooting means a target shooter’s FOC percentage can be on the lower end. Arrows used for target shooting tend to be more forgiving. Somewhere between 7% and 15% tends to be the ideal FOC for target shooters. Obviously, there takes a little experimentation to find what work best for you, but this works best for most archers.

FOC For Hunting

Perfect arrow balance is crucial when calculating FOC for hunting. If arrow balance is off, arrow flight will be eradict and may cause you to miss or wound an animal. FOC is especially important for hunters who shoot fixed-blade broadheads. This is because it directly affects arrow flight and trajectory. Fletchings lose their leveraging power if an arrow’s balance point and physical midpoint are overly close. Fletchings lose even more leveraging power if the arrow’s balance point is located behind the physical midpoint, leading to unstable arrow flight.

Another consideration is kinetic energy vs momentum. A low FOC will lead to higher kinetic energy, but less momentum. A higher FOC will have lower kinetic energy, but more momentum. Balance is key as kinetic energy will provide distance where momentum will provide more penetration. Generally speaking, you’re looking for an FOC between 10% – 20% in hunting situations. This higher FOC allows for better arrow flight and increased penetration, both of which are ideal for hunting situations.

How Does F.O.C. Affect Arrow Flight?

The more weight contained in the front half of the arrow, the more forward the arrow’s center of balance is going to be. Generally speaking, a high front of center will first fly with a good amount of stability but will soon begin to lose its trajectory, causing it to quickly nose-dive. In contrast, a low front of center will shoot flatter, but the downside is that arrows tend to be less forgiving and fly eratically.

Archers who prefer shooting long distances must figure their front of center calculations to avoid experiencing any accuracy problems. Sometimes the slightest flaws aren’t noticed when shooting over short distances, but cause issues at distance. It’s important to take this into consideration and make the right decision for your shooting environment.

How To Calculate Your Arrow’s F.O.C.

If you’re wondering how to calculate FOC, here’s how you do it. First, place all of your archery accessories on the shaft, i.e. vanes, point, nock, and anything else. Once you’ve properly set up your arrow, follow the instructions below to calculate your FOC, all you need is a tape measure and a calculator to get started.

  1. Measure the distance from the bottom of the nock groove to the end of the shaft and then divide by two to find the arrow’s overall length.
  2. Finding the balance point is your next step, which is the area where the arrow perfectly balances (you can simply balance on your finger). Mark the balance point of your arrow and then measure from this point to the throat of the nock.
  3. Now subtract your measurement from step number one from your measurement from step two and multiply by 100. Divide this number by the arrow’s overall length to get your exact FOC.

If you’re front of center number is vastly different from the recommended range of 7% to 15% for target shooting, you may want to add or remove some weight to or from the front or rear of your arrow. For bowhunters, FOC is 8% to 11% for field points and 12% to 20% for broadhead arrows. The majority of the world’s best target shooters use a 9% to 12% FOC to provide them with the most accuracy.

How To Change Your F.O.C.

As not all expert archers agree on whether there’s indeed an ideal front of center percentage, you should feel free to play around with your FOC calculations. As you play with your FOC percentage, first try to go higher to find your ideal FOC. A larger front of center has more of an impact and tends to penetrate better. Avoid going over 20% as it is possible to go too high, which will make your arrows too point-heavy and in turn underperform at distance.

If you find your arrows are flying erratically, try using a heavier arrow tip, this will increase your FOC and help smooth out your arrow flight.

Adding Weight To The Front Of The Shaft To Modify The Balance

Need to increase your FOC? Then you’ll need to add more weight to the front part of the arrow. Adding a heavier insert or tip is your best option, as well as using lighter fletching. Be sure to increase in small increments when finding your ideal FOC as adding a heavier tip will weaken your arrow spine. You can also choose to replace heavy vanes with lighter vanes or use feathers to lighten the weight of the rear part of the arrow.

Adding Weight To The Rear Of The Shaft To Modify The Balance

Need to decrease your FOC? Then you’ll need to reduce tip weight or increase weight at the back of the arrow. You can add weights or inserts to the backend of the shaft, use lighted nocks, pin nocks, arrow wraps, or heavier vanes. Any of these options will increase the weight at the rear part of the arrow, decreasing your FOC.

What F.O.C. Works Best For Me?

As front of center drastically affects arrow flight and trajectory, you’ll need to narrow down a percentage that works for your shooting situation. While you want to have your arrows a little heavier at the front to assist with forward momentum and arrow flight, it can be tricky to find your perfect front of center percentage. Add too much and your arrow will quickly drop. Too low and you’ll experience erratic arrow flight.

So what do you do? Start experimenting. Have fun with your arrows. Be sure to play around with your FOC percentage until you find what works best for you. As long as you’re somewhere between 8% and 15%, you’re setting yourself up for quality flight, distance, and penetration. Once you’ve found what works best for you, you’ll know how to set up your arrows in the future to achieve the best results.


Now that you know the answer to what is FOC, you can complete your arrow set up to achieve better results. You’ll not only experience an improvement in the overall performance of your arrows, you’ll also experience an improvement in arrow accuracy. Be sure to take your time when figuring out your FOC percentage so you can shoot with confidence.

Calculating your FOC is especially important if you plan on participating in long-range shooting competitions that utilize strict shooting rules, like the Olympics. While front of center isn’t as relevant when taking short-range shots, it still makes a noticeable difference in arrow accuracy. So, get out there, find what works best for you, and increase your accuracy!

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