Gear, Parts and Accessories

Estimating Range With A Mil-Dot Reticle

It’s a common feature found on many scopes and other optics, but what exactly is a Mil-Dot reticle, and how do you use it? It’s important to make clear the distinction between Minutes of Angle and Mils. A Mil, or milliradian is equal to about 3.44 MOA. Most reticles are marked in milliradians using Mil-Dots, while adjustments through the turrets are usually made in fractions of an MOA.

Variable magnification scopes come in two types: First Focal Plane (FFP) or Second Focal Plane (SFP) reticles. Most American scopes have the reticle on the second or rear focal plane, so that the reticle stays the same size as the zoom is changed. European style scopes have the reticle on the first or front focal plane, such that as the magnification on the scope is increased the reticle increases in size. European Mil-Dot reticles are accurate for range estimation at any zoom level. For American style rear focal plane reticles on variable magnification scopes, the Mil-Dot size estimation is only accurate at a certain zoom level. For most variable scopes with a second focal plane reticle the proper magnification is 10x, though this does vary depending on the manufacturer. Consult your owner’s manual to determine what zoom level your Mil-Dot reticle is designed for.

The first step in using a Mil-Dot reticle is accurately measuring the size of a target in Mils. Once a target of known size is measured in Mils in the scope, a simple calculation is used to estimate range to the target and compensate for bullet drop. Accurately measuring the target in Mils is not easy, and it is necessary to get an approximation down to around one tenth of a Mil. In the photo shown to the left, the chest of the deer reads at approximately 0.3 Mils. Shown here on the internet, this measurement is fairly easy to see, but when staring down a scope that you are struggling to hold steady at a target that may not be holding still, it becomes much more difficult to get an accurate Mil read.

The formula for computing the estimated range is accomplished by taking the target size in yards, multiplying that by 1000 and then dividing the result by the target measurement in Mils. The result is the approximate distance in yards to the target. The formula for meters is the same, with the target size in meters multiplied by 1000 and divided by the target measurement in Mils giving the approximate range in meters.

So, if you have a man sized target that is six feet tall, you would compute Target size in yards (2) multiplied by 1000 and divided by the measurement in Mils. If a six foot tall target, for example, measures 3 Mils, the formula would be 2 X 1000 / 3= 667 yards.

Size of Target In Yards X 1000 / Mils read = Range to Target (in yards) The formula is the same for meters: Size of Target In Meters X 1000 / Mils read = Range to Target (in meters) There are two ways to compensate for bullet drop. One is to use hold-over. This involves changing the point of aim to be somewhere other than the center of the cross hairs of a scope. The other is to adjust the turrets the appropriate number of clicks until the target can be centered in the cross hairs. Once the range is known, the shooter can then make the necessary adjustments to the elevation using the scope turrets, or hold over the proper amount using the Mil-Dots as an aiming system. If you know your rifle is zeroed at 300 yards for example, your target is an estimated 400 yards and your bullet drop at 400 yards is 15 inches, then you would hold just slightly less than 1 Mil high (1 Mil-Dot is 14.4″ at 400 yards).

There are numerous tools on the market that make range estimation using a Mil-Dot system fast and easy. Some use a slide rule type setup where the target size and measurement in Mils is input to the tool, and the range estimate is then shown. Others use a spreadsheet to allow the shooter to quickly find the range estimate. You can download your own “cheat sheet” by clicking on the image shown to the right. Simply save the *.PDF file to your computer and print it out on a plain sheet of 8.5×11 paper. Fold the paper into thirds and cut or tear carefully along the creases and you will have three copies of our Mil-Dot Range Estimation guide you can laminate or simply fold up and take with you.

Here are a few more quick references to help you quickly and easily estimate range using a Mil-Dot reticle: The average adult deer chest is around 18 inches tall.  At 100 yards, that deer chest will take measure 5 Mil-Dots, 2.5 dots at 200 yards, 1.6 dots at 300 yards, and 1.25 dots at 400 yards. For calculating holdover, remember that 1 Mil is about 3.44 MOA, so 1 Mil at 100 yards is about 3.5 inches. At 200 yards, that same Mil is about 7 inches, at 300 a single Mil is 12 inches, and at 400 yards is just over 14 inches.

The only way to get good at using your Mil-Dot reticle to estimate range is to practice. Take a hike and set up multiple targets of known size (1 yard/3 foot squares of poster board on stakes work great) at various distances from your shooting bench. Head back and get out your estimation guide, calculator, or pencil and paper and find your measurements and estimated range. Confirm your estimated range figures with a laser range finder, GPS, or other device. Soon you’ll be able to quickly and easily estimate the range to nearly any target.

The Mission of Cheaper Than Dirt!'s blog, The Shooter's Log, is to provide information—not opinions—to our customers and the shooting community. We want you, our readers, to be able to make informed decisions. The information provided here does not represent the views of Cheaper Than Dirt!

Comments (10)

  1. I did have to chuckle at “range at approximately 1,389 yards. Too far away for an ethical shot.”.
    Buddy, I hunt with a 30-30. You can subtract 1000, and it Still ain’t an ethical shot. 😉

    Thought I would share this. Calibrate your scope at the range with a grid target after learning this.
    If you have a variable power scope and the calibration (cal.) for the subtensions of the reticle is say 14x on a 6.5-20 power scope you can determine the hash mark spacing at say 6.5x, 8x and 20x. by using the following formula.
    Divide the cal. (14x) by the desired power, say 6.5x or 20x and then multiply the cal. subtension size by this answer. You can now make a chart for hold over or even ranging.
    Here we go. 14x/20x=.7, 14x/8x=1.75 and so on. Now take the answer, say .7 for the 20x. Multiply the answer against the cal. subtension size.
    If the subtension, (mil-dot) spacing is 3.6” at 14x it will be 3.6 x .7= 2.5” @20x. 3.6” x 1.75= 6.3” @8X and 3.6 x 2.1=7.56” @6.5x
    If you want to range with this concept you convert the standard ranging formula of: target size x 27.77 (100/3.6) divided by Mils. (.1-1) = distance in yards.
    Use the different power conversion number as the multiplier against the known target size.
    We get the multiplier by dividing, 100/conversion number. At 20x the new size is 2.5” so 100/2.5=multiplier of 40. So now we have target size x 40 rather than 27.77 and we then divide that by the mil dot. for distance in yards at 20x rather than 14x.
    A 10” deer head spaced at ½ mil at 6.5x power is how far away? Put this info on a chart beforehand. Let’s say you already know the deer is 300 yards away because you have been hunting here before or ranged it. But just for example: 14x/6.5x=2.1, 3.6x 2.1=7.56” conversion, 100/7.56=13.22 multiplier, Target size, (10”) x 13.22/Mil. (.5)=264 yds. If it were .4Mil=330 yds. .3Mil=440 yds.
    Some elevation may be needed.
    How much you ask? Let’s say your 30. 06 drops from your 2” high sight in at 100 yards to -7” low at 300 yds. We know that each hash mark is 15.3” apart @ 100 yds. at 6.5x so let’s figure here ahead of time not in the stand.
    7”/ 3 (300 yds.)= 2.3” (MOA) of elevation @100 yds. needed to make up for the 7” drop zero at 300 yds. 2.3” /15.3”(@6.5x) between each dot = .15 mil, the size of 3 cross hairs each measuring .05M.
    Depending on the subtensions for your scopes reticle. See manufactures’ info.
    Sound overdone, well this can help you understand that a little adjustment at 6.5x goes a long way compared to say 20x. At 20x the same 7” correction looks like this. 2.3”/2.5” = .9M almost a full mill.
    When I refer to Mil in this case I mean the hash marks of the reticle. You can us whatever terms you like.

    Duplex scope for your pistol: say a 2x-6x cal. at 6x. Whatever it take to determine the subtension (cross hair, hash mark space or dot size) from the manufacture. 6x / 4x =1.5
    1.5 x 6”= 9” 2x = 6/2=3, 3×9”=18”@2x power

  3. Johan- There are full books available about shooting long range and different types of scopes and reticles. It can be confusing, especially when working in two or more different systems…Mils, MOA, and inches. To answer your first question about magnification and measuring range. It depends on where the the reticle is located inside the scope. It is usually etched in the glass in the first or second focal plane. Most scopes have the recticle etched into the second plane. The measurement will only be accurate at one magnification. On high power scopes, this is usually 10x or 12x. Reticles on the first focal plane are usually more expensive, but the measurements are accurate at all magnifications. It will change size as the magnification increases or decreases.

    The answer to your second question is you need a ballistic calculator. You can buy them for your handheld device like a smartphone or similar device. There are several free versions available that you can use online too. Winchester and Berger Bullets are two that I use. You enter in the caliber, bullet weight, velocity, and a few more variables, and it will give you a fairly close estimate of the bullet drop and drift.

    I hope I didn’t confuse you!

  4. Hi I want to thank you very much for this information. I have a question puzzles me?? Does reading by mil dot reticle if different magnification power. For example, can you read the distance to the goal if it was 10x or 16x or more? And please, how can I get information about the different types of bullet caliber at different distances and how will I know how much clicks can be used on several ranges? Thanks. You are truly wonderful. I wish to respond as soon as possible.

  5. It’s the WERM rule. Standard sniper math. (W)idth x1000 (E)quals (R)ange x (M)ils. If you have two factors you can always find the third.

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