What is MOA? MOA stands for minute of angle. There are 360 degrees in a circle and each degree is divided into 60 minutes. If we round to the nearest 1⁄100 of an inch, at 100 yards 1 degree measures 62.83 inches. One MOA, 1⁄60 of that, measures 1.047 inches. While 1 MOA at 100 yards equals 1.047 inches, at 200 yards it equals 2.094 inches (2 x 1.047). To calculate MOA at any distance, multiply 1.047 by the distance in yards and divide by 100.
What is a MIL? MILS (milliradians) is another angular measurement. There are 6.2832 (π x 2) radians per circle. There are 1,000 mils per radian so, there are 6,283.2 mils in a circle. There are 21,600 MOA in a circle, so a little quick division determines there are 3.4377 MOA per mil. At 100 yards, 3.4377 MOA equals 3.599 inches (3.4377 x 1.047). Rounded up, one mil equals 3.6 inches at 100 yards. A mil is so large, it’s broken into tenths in order to make precise adjustments. If you have a riflescope with mil adjustments, each click equals 1⁄10 mil. A tenth of a mil equals .36 inch or .9144 centimeter at 100 yards. Since 1⁄10 of a mil is an angular measurement, it will be slightly larger at 100 meters than at 100 yards because 100 meters equals 109.361 yards. At 100 meters, 1⁄10 of a mil equals .9999 centimeter. Practically speaking, 1⁄10 of a mil equals 1 centimeter at 100 meters. Because mil, like MOA, is an angular measure, the length it represents increases with distance. For example, 1 mil at 100 yards equals 3.6 inches and 7.2 inches at 200 yards. To calculate how many inches are in a mil at any distance, multiply 3.6 times the distance in yards and divide by 100.