I've been doing a lot of research on FOC calculations and I've found a fork in the road..... Some recommend you measure from the throat of the knock to the end of the shaft, and others say to the end of the point/broadhead. Measuring to the end of the point/broadhead makes the most sense to me, but was curious as to what you guys do.
I did both. It's just good to know both so i use it as an esitmate. The Formula would be (X-Y)/L = FOC L is the length of the arrow, I prefer from the throat of the knock and the tip of the broadhead/field point. where X is the length of the arrow divided by 2 and Y is the the length of the tip to the balance point So when I calculate it for my Carbon Injexions with Deep Six Tips, my arrow length is 26.25 and the balance point is 9.75 exact Half of the arrow is 13.13 and so it comes out like this. (13.13-9.75) / 26.25 = FOC 3.38 / 26.25 = FOC FOC = 0.1286 or converted to percents ---> 12.86% Remember that a good FOC is between 7% to 15% You also can use this "click"------> FOC Calculator I hope this helps.
