QUICK TIPS

How To Measure Arrow FOC

The FOC measurement of an arrow shaft is simply the percentage of the shaft length that lies forward of the centre point of the arrow between the centre point and the balance point. To find FOC first divine the arrow length by two (A in the Graphic) and mark the exact centre of the shaft. Then balance the arrow on a kitchen-knife blade (or any other sharp edge) and mark that exact spot.

Now measure the distance between the two marks (B in the Graphic). Dividing the arrow length into FOC length (B)then multiplying that by 100 will give you your FOC percentage. So on a 30-inch arrow with a balance point that is two inches forward of the physical centre of the shaft, you have 2/30=.07X100=7%. It is really that simple.