MOA Calculator

MOA Calculator converts minutes of angle to inches or centimeters at any distance and turns a group size or miss into MOA. It also gives scope clicks, the MRAD value and the range.

MOA Calculator for Size, Angle and Distance

MOA stands for minute of angle, which is one sixtieth of a degree. It is an angle, so the width it covers grows with distance. The National Shooting Sports Foundation gives it as about 1 inch per 100 yards, or 1.047 inches to be exact.

The MOA Calculator works in three directions, chosen under Find. Size at a Distance converts MOA to inches or centimeters on the target. MOA From a Size turns a group size or a miss into an angle. Distance to a Target estimates range from a target of known size.

The default is 2 MOA at 500 yards, which covers 10.47 in. The cards add the same angle in MRAD, the number of clicks to dial on the chosen turret, the metric equivalent, and what that angle covers at 1,000 yards. Angles can also be entered in MRAD or in inches per 100 yards.

MOA Formula

The exact formula treats the size on target as an arc. With the size and the distance in the same unit, one MOA covers the distance times π divided by 10,800. The MOA Calculator uses this form for every result.

$$size = \frac{\pi \times MOA \times distance}{10800}$$

Rearranged, it gives the angle from a size and a distance. This is how to calculate your MOA from a group measured on paper, or from the gap between the point of aim and the point of impact.

$$MOA = \frac{10800 \times size}{\pi \times distance}$$

For inches and yards, the same thing reduces to a shortcut. Divide the distance in yards by 100, multiply by 1.047 and multiply by the number of MOA. At 500 yards, 2 MOA is 2 × 5 × 1.047 = 10.47 in.

$$inches = MOA \times \frac{yards}{100} \times 1.047$$

MOA Chart by Distance

The chart converts MOA to inches from 100 to 1,000 yards. It also shows one click of a 1/4 MOA scope, one MRAD and the shift from a 20 MOA rail. The MOA Calculator draws the same chart for any angle entered.

So a 1 MOA target at 600 yards is 6.28 in across, 3 MOA at 100 yards is 3.14 in, and 2 MOA at 100 yards is 2.09 in. At 1,000 yards each MOA is worth 10.47 in, which is why small angle errors matter so much at long range.

In metric, 1 MOA at 100 m is 2.91 cm, or 29.09 mm. That is 1.145 in, a little more than at 100 yards because 100 m is the longer distance. One MRAD at 100 m is exactly 10 cm. Switch Result Units to Centimeters and Meters for a metric chart.

Inches to MOA and Group Size

MOA From a Size is the inches to MOA calculator. Enter the size and the distance, and it returns the angle. One inch is 0.955 MOA at 100 yards, 0.477 MOA at 200 yards, 0.318 MOA at 300 yards and 0.191 MOA at 500 yards.

The same setting is a group size MOA calculator. A 1.5 in group at 100 yards is 1.43 MOA. A 3 in group at 500 yards is 0.57 MOA, which is the better result even though the group is twice as wide. Measuring in MOA lets groups shot at different distances be compared fairly.

A smaller MOA means tighter shooting, so 1 MOA is better than 2 MOA for a group. A rifle and load that hold 1 MOA are a common benchmark for good accuracy, and anything under that is called sub-MOA. For a red dot the number is the dot size, where a 2 MOA dot covers 2.09 in at 100 yards.

Scope Clicks and the 1/4 MOA Turret

Most MOA scopes move 1/4 MOA per click, so 1 MOA takes 4 clicks. A 1/8 MOA turret needs 8 clicks and a 1/2 MOA turret needs 2. The click count for an angle does not change with distance. At 400 yards, 1 MOA is still 4 clicks, and each click moves the impact 1.05 in.

As a 1/4 MOA calculator, the second card rounds any angle to whole clicks. A shot 2 in low at 100 yards is 1.91 MOA, or 7.64 clicks, so 8 clicks is the closest setting. A 10 in correction at 200 yards is 4.77 MOA, which is 19 clicks.

Some turrets are marked in inches per 100 yards, often called shooter’s MOA or IPHY. One IPHY is exactly 1 in at 100 yards, so it is 4.7% smaller than a true MOA. The click menu has a 1/4 Inch at 100 Yards option for those scopes.

MOA to MIL Conversion

A milliradian, written MRAD or mil, is one thousandth of a radian. One mil equals 3.438 MOA, and one MOA equals 0.291 mil. To convert MOA to mil, divide by 3.438. The first card of the MOA Calculator does this for every result.

So 30 MOA is 8.73 mils and 40 MOA is 11.64 mils. Neither unit is better. MOA pairs naturally with inches and yards, and mils pair with centimeters and meters. What matters is that the reticle and the turrets on a scope use the same unit.

20 MOA Rails

How much is 20 MOA in inches?

It is 20.94 in at 100 yards and grows with distance, reaching 104.7 in at 500 yards and 209.4 in at 1,000 yards. A 20 MOA rail tilts the scope by that fixed angle, which frees up more of the scope’s upward travel for long shots.

Can you shoot 100 yards with a 20 MOA rail?

Yes, as long as the scope has enough downward adjustment left to take up the tilt. The rail shifts the aim by 20.94 in at 100 yards, so the scope needs about 20 MOA of travel below its center. A scope with 60 MOA of total elevation has about 30 MOA each way and can still zero at 100 yards.

Do I need a 20 MOA base for 600 yards?

It depends on the bullet drop and the scope. Find the drop at 600 yards in MOA and compare it with the upward travel the scope has left after zeroing. The base is needed only when the drop is larger. Drop comes from the load’s velocity and drag, which starts with the Ballistic Coefficient Calculator.

MOA Calculator for Distance

The third setting estimates range. Enter the real size of the target and the angle it spans in the reticle. A target 18 in wide that spans 2 MOA is 859.4 yards away. The same target spanning 1 MRAD is exactly 500 yards away.

This method is only as good as the reading. A small error in the angle moves the distance a lot, and the target size must be known. With no air at all, a bullet fired level drops like any falling object, which the Horizontal Projectile Motion Calculator shows, so real holdovers always come from a ballistics table.