Minute of angle (1/60 of a degree) is the angular unit used by shooters, scope makers and surveyors. A rifle that groups within 1 MOA puts its shots inside about one inch at 100 yards. Many scopes adjust in ¼-MOA or 0.1-MIL clicks.
How to use the MOA Calculator – Minute of Angle
- Distance
- Spread (group size or correction)
Results update as you type, every field has its own unit menu, and everything is calculated in your browser.
How it works
Enter the target distance and the spread (group size or correction you need). The calculator returns the angle in MOA and milliradians and the equivalent size at the standard distances.
Inputs explained
| Field | What to enter |
|---|---|
| Distance | Units: yd, m, ft, km |
| Spread (group size or correction) | Units: in, mm, cm, ft, m |
What each result means
- Angle in MOA = deg(atan([Spread (group size or correction)]÷[Distance]))×60
- Angle in MIL (mrad) = atan([Spread (group size or correction)]÷[Distance])×1000
- Size at 100 yards = tan(atan([Spread (group size or correction)]÷[Distance]))×91.44
- Size at 100 metres = [Spread (group size or correction)]÷[Distance]×100
- Clicks at ¼ MOA = [Angle in MOA]×4
Example values
How the main result changes when Distance changes and everything else stays at the example values above:
| Distance (yd) | Angle in MOA (MOA) |
|---|---|
| 50 | 1.9099 |
| 75 | 1.2732 |
| 100 | 0.9549 |
| 125 | 0.7639 |
| 150 | 0.6366 |
| 200 | 0.4775 |
Formula
MOA = arctan(size / distance) in arcminutes, MIL = size / distance × 1000
1 MOA ≈ 1.047 in at 100 yd ≈ 2.91 cm at 100 m
Worked example
Inputs — Distance: 100 yd; Spread (group size or correction): 1 in.
Results — Angle in MOA = 0.9549 MOA; Angle in MIL (mrad) = 0.2778 mil; Size at 100 yards = 1 in; Size at 100 metres = 2.7778 cm; Clicks at ¼ MOA = 3.8.
Key terms
- Minute of angle
- 1/60 of a degree.
Frequently asked questions
How big is 1 MOA at 100 yards?
About 1.047 inches.
What is a MIL?
A milliradian: 1/1000 of the distance – 10 cm at 100 m.
How many MOA in a MIL?
About 3.438.
What is "shooter's MOA"?
A rounded 1 inch at 100 yards, slightly smaller than a true MOA.