What Are MOA, MIL, and MRAD?

Scopes are a crucial part of long-range shooting and hunting, but just as each hunter has their own unique style, there are different types of scopes. Although friends and fellow hunters might recommend their personal favorite, scopes are a subjective piece of equipment - meaning it is more about your personal preference than what is ‘best’.

MOA and MRAD are two angular measurement systems used in optics. MRAD is also called MILS and it is a metric measurement, while MOA is an imperial measurement. These systems are what we use to adjust or sight in our optics with a high level of accuracy at various ranges.  

What’s MOA?

MOA stands for Minute of Angle and utilizes a system of measurements that dates all the way back to the Mesopotamians nearly 6,000 years ago. The Babylonians utilized a base-60 number system for mathematics and trade, and this was passed on to the Egyptians, who realized that six perfect triangles with angles of 60 degrees each fit into a circle, thus giving the circle 360 degrees. Coincidentally, 360 is also the smallest number that is easily divisible by all numbers between 1-10 except 7, which makes dividing it easy.

In each circle, there are 360 degrees and within each degree there are 60 minutes. Thus, a circle consists of 360 x 60 = 21,600 minutes.

So, what does this actually mean when you’re using a scope?

Imagine you’re at the center of a circle, and the target you are shooting at is on the edge of the circle approximately 100 yards away. Divide your circle into 360 degrees, walk out to your target, and measure the difference between each degree. You will get 62.83 inches as the distance between each degree. Divide that number by 60 to get the minutes of angle, and you come up with 1.047 inches. This means at 100 yards, each MOA is approximately 1 inch. 

Shooter’s MOA

Since the MOA at 100 yards is calculated to be 1.047 inches, it can be approximated to 1 inch per hundred yards, sometimes referred to as the ‘shooter’s MOA’. This also makes calculations very simple - at 200 yards, an MOA is approximately 2 inches; at 300 yards it’s approximately 3 inches.

Most targets you will see for shooting have 1 inch squares for this exact reason. If all your shots are clustered in a one inch square at 100 yards, it can be said you have a “one-MOA gun”. 

MOA and Scope Adjustments

Now that we’ve uncovered what MOA stands for, how does it relate to the scope on your gun? If you have an MOA scope, most turrets utilize 1⁄4 clicks. This means that the fourth click represents a full MOA, or each click is ¼” at 100 yards. Normally, the full MOA hash marks are represented by longer lines on the dial.

Once you’ve calculated how far you need to adjust your scope in MOA, simply multiply by four to determine the number of clicks you need to turn.

An example:

At 200 yards, your grouping averages 3” high and 2.5 inches left of the bullseye. How should you adjust your scope?

3” x (200 yards / 100 yards) = 6 MOA high; 6 MOA x 4 = 24 clicks down on ¼ click turret

2.5” x (200 yards / 100 yards) = 5 MOA left; 5 MOA x 4 = 20 clicks right on ¼ click turret

MRAD and MIL

A milliradian (MRAD) is a different angular measurement. Milli stands for 1/1000, so a milliradian is 1/1000th of a radian. A radian is the angle of a distance around the circumference of the circle that is equal to the radius, the distance from the center to the edge. There are 6.238 radians to each circle, so there are 6,238 milliradians in each circle.

When calculating MRAD is a scope, it is generally just referred to as MIL. Just like MOA, MILs increase linearly as distances increase. At 100 meters, 1 MIL is 10 cm. At 200 meters, 1 MIL is 20 cm. 

MRAD and Scope Adjustments

Just like with MOA, the turrets that adjust your scope will have a specific MIL that each click represents. Most utilize a 1/10 MIL adjustment, although it is always good practice to double check the instruction manual that came with your scope. Similarly to the math above for MOA, to adjust the scope simply turn the turret 10 x MILs needed to get the correct positioning.

MOA to MRAD Conversions

As we noted earlier, there are 21,600 minutes and 6,238 milliradians in a circle. By dividing 21,600 by 6,238, we get that there are 3.4377 MOA per MIL. We already know that 1 MOA = 1.047 inches at 100 yards, so to calculate the MIL we multiply 1.047 x 3.4377 = 3.599 inches, which gets rounded to 3.6 inches. So, one MIL is equal to 3.6 inches at 100 yards.

To quickly convert between the two, you can utilize 3.5 as a round calculation of the 3.438 MOA per MIL noted above. To convert MILS to MOA, multiply by 3.5. To convert MOS to MILS, divide by 3.5 . 

Which One Should You Use?

There’s no correct answer for whether you should use MOA or MRAD on your scope. But there’s a couple of factors you should consider:

What is your purpose? If you’re getting into long-range shooting or tactical usage, MRAD is the standard. 

What do your hunting partners and friends use? Having a common language is important.

What’s easiest for you? Does your brain think more in inches and yards, or meters and centimeters?

MOA and MRAD represent the same concept in two different measurement systems. There’s no right or wrong option, but it may take playing around with each style to determine what is most comfortable to you as the user. Consider different factors that might affect your hunting or shooting style and determine what style scope is the best fit for you. 

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