MIL is an angular measurement shooters use to describe accuracy and make aiming corrections.
MIL stands for milliradian. It’s a way of measuring an angle, and shooters use that angle to measure targets and make scope adjustments.
Think of it as a measurement that is shaped like a tiny piece of pie. It starts at a point, and then spreads outward as distance increases. The farther away the target is, the larger space that same angle covers.
One MIL is 3.6” at 100 yards. As distance increases, the linear distance grows, but it’s still 1 MIL. So at 200 yards, 1 MIL is 7.2”, and at 300 yards it’s 10.8”.
Scopes also use MIL for adjustments. When you turn a MIL-based turret, most scopes move the point of impact by 0.1 MIL per click. The distance is irrelevant. It’s just moving the impact by 0.1 MIL. Using the example above, at 100 yards a single click would move the point of impact .36”, and at 200 yards .72”, and that measurement continues to increase as the distance increases, but is still always 0.1 MIL.
For this reason, when using a MIL system, it’s always best to talk and think in the system you’re using; that way you escape having to do any conversions and can just make the correct adjustments on your optic no matter what the yardage is.
The simple version is:
MIL is an angular measurement shooters use to describe accuracy and make aiming corrections.
If you want to compare MILs with the other common angular measurement system used in rifle scopes, read our Short What Is MOA?