MOA Calculator — Minute of Angle

Use the MOA calculator to find the relationship between spread, distance, and shooting angle.

Size at 100 yards1.0472 inches26.6 mm

Angular size1 MOA0.016667 degrees, 0.2909 milliradians

One MOA at 100 yards1.047198 inchesthe true value — the familiar "one inch at 100 yards" is a convenient rounding about 4.5% low

One MOA at this range1.0472 inches

One milliradian at this range3.6 inchesa mil is 3.6 inches at 100 yards, and 3.438 MOA

Correction needed2.8648 MOAto move the point of impact 3 inches at 100 yards

Clicks required11.46at 0.25 MOA a click — round to 11

One click moves0.2618 inches at this range

At 200 yards2.094 inchesthe same angle — group size grows in direct proportion to range

At 300 yards3.142 inchesthe same angle — group size grows in direct proportion to range

At 500 yards5.236 inchesthe same angle — group size grows in direct proportion to range

At 1000 yards10.472 inchesthe same angle — group size grows in direct proportion to range

The formula

1 MOA = 1/60 degree; group size = range × angle in radians

An angle, not a length

A minute of arc is one sixtieth of a degree, so it is an angle and the distance it subtends grows in proportion to range. One MOA covers about an inch at 100 yards, two inches at 200, ten inches at 1000. That proportionality is the whole reason accuracy is quoted this way: it lets one figure describe a rifle at every distance.

The familiar "one inch at 100 yards" is a rounding. The true value is 1.047 inches, so the shooting convention runs about 4.5% low. It is harmless at short range and reaches half an inch of error by 1000 yards, which is why long-range work uses the exact figure or switches to milliradians.

A milliradian is the cleaner unit for arithmetic: it is exactly one part in a thousand, so at 100 metres one mil is 10 centimetres, and the sums need no conversion constants at all. One mil is 3.438 MOA.