Minute of Angle, or MOA, is an angular unit used throughout precision and practical rifle shooting to describe group size, optic adjustments, reticle measurements, and the corrections you dial or hold when your point of impact doesn't match your point of aim. It's one of the two principal angular systems found in modern rifle optics, alongside MRAD — most scopes are built around one system or the other, and knowing which one you're working with matters before you ever touch a turret.

This module covers MOA on its own. MRAD gets its own module once the fundamentals here are solid.

What Is A Minute Of Angle?

A full circle contains 360 degrees. Each of those degrees is further divided into 60 minutes of angle — so a complete circle contains 21,600 minutes of angle in total. One Minute of Angle is simply 1/60th of a single degree.

The important thing to take from this is that MOA measures an angle, not a fixed physical distance. It behaves the same way a wedge or a beam of light does — narrow at the source, wider the further it travels. What changes with range isn't the angle itself; it's how much physical space that angle covers once it reaches the target.

Why MOA Grows With Distance

The angle of 1 MOA never changes. What changes is the linear distance that angle subtends — the area it covers — as the target gets further away. Think of it like a torch beam: narrow close up, wider the further it travels, even though the torch hasn't changed how wide it shines.

True MOA Reference Table

Distance (Yards)	1 MOA (Inches)	Distance (Metres)	1 MOA (mm)
100 yd	≈ 1.047 in	100 m	≈ 29.1 mm
200 yd	≈ 2.094 in	200 m	≈ 58.2 mm
300 yd	≈ 3.141 in	300 m	≈ 87.3 mm
500 yd	≈ 5.236 in	500 m	≈ 145.4 mm

These are the linear subtensions of a 1 MOA angle at each stated distance — not separate measurements, just the same angle measured further down range.

True MOA vs Shooter's MOA

The exact value of 1 MOA is 1.047 inches at 100 yards, or 29.1mm at 100 metres. For practical, fast fieldwork, many shooters round this to 1 inch at 100 yards and approximately 30mm at 100 metres. This rounded convention is called Shooter's MOA (SMOA).

SMOA is convenient for quick mental maths at the range, but it's an approximation, not the exact angular value — and the gap between the two isn't fixed at "1 inch equals 30mm" either. The difference is small at short range but accumulates as distance or the size of your correction increases. For a short-range zero confirmation it won't matter. For a correction at longer distance, working from true MOA values will keep your maths honest.

Where This Goes Next

MOA isn't just a definition — it's the unit you'll use for two practical jobs later in this chapter. In 4.2, you'll use this same value to convert a bullet-hole group's physical size into an angular measurement, so groups shot at different distances can be fairly compared. In 4.3, you'll use it to work out exactly how many turret clicks a correction needs, and dial it in with confidence.

Common Mistakes

Key Takeaway