The MilDot Reticle

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Simply put, the Mil-Dot is a range estimating reticle that was developed for military applications. The space between the dot centers subtends one milliradian (Mil). One Mil subtends 3.6" at 100 yards, or 36" at 1,000 yards.

This reticle was developed in the late 1970s to help U.S. Marine snipers estimate distances, and is now standard for all military branches. The space between dot centers subtends one milliradian (mil) hence the name mil-dot. Contrary to popular belief it does not stand for "military dot". One mil subtends 3.6 inches at 100 yards or 36 inches at 1,000 yards. To use this system effectively you must know the size of the target. For instance most people are an average of 6 feet tall or 2 yards. The formula used for determining range to the target is (size of target x 1000 divided by number of mils the target covers).

Height of target (yards) X 1,000 = Range (yards)/
Height of target (mils)

You can do these calculations with a calculator or use a reference table like the ones listed below. But remember that your answer is only as accurate as the numbers you plug into the formula. An error of just a 1/4 mil will cause an error in target range. Also an error in estimating the size of your target will cause an error in target range.

The top line on the table represents the size of the target as measured in feet or inches. The second line represents the conversion of the foot measurements to yards. The left column shows the mil measurements to the nearest 1/2 mil. The mil scale can be split to the nearest 1/8 mil for a more accurate range measurement. To use the table follow the instructions below.

  1. Estimate height of target and locate across the top.
  2. Measure height of target in mils and locate down the side.
  3. Move down from the top and right from the side to find the range in yards.

Range Estimating with the Mil-Dot Reticle

Dots are spaced in one mil (milliradian) increments on the crosshair. Using the mil formula, a table can be created like the ones above that is based on the size of the object being targeted. Just look through the scope, bracket the object between dots, and refer to the table for an estimated distance to target.

The radian is a unit-less measure which is equivalent in use to degrees. It tells you how far around a circle you have gone. 2 PI radians = 360 degrees. Using 3.14 as the value of PI, 6.28 radians take you all the way around a circle. Using a Cartesian coordinate system, you can use "x"- and "y"-values to define any point on the plane. Radians are used in a coordinate system called "polar coordinates." A point on the plane is defined, in the polar coordinate system, using the radian and the radius. The radian defines the amount of rotation and the radius gives the distance from the origin (in a negative or positive direction).

The radian is another measurement of rotation (the degree/minute/second-system being the first). This is the system used in the mil-dot reticle. We use the same equation that we used before, but, instead of your calculator being in "degree" mode, switch it to "radian" mode. One milliradian = 1/1000 (.001) radians. So, type .001 into your calculator and hit the "tangent" button. Then multiply this by "distance to the target." Finally, multiply this by 36 to get inches subtended at the given distance. With the calculator in "radian" mode, type:

tangent(.001)*100*36 = 3.6000012

So one milliradian is just over 3.6 inches at 100 yards. If we extrapolate, two milliradian equal about 6 feet at one-thousand yards.

The mil-dot reticle was designed around the measurement unit of the milliradian. The dots themselves were designed with this in mind and the spacing of the dots was also based upon the milliradian. This allows the shooter to calculate the distance to an object of known height or width. Height of the target in yards divided by the height of the target in milliradians multiplied by 1000 equals the distance to the target in yards. For example, take a 6-foot-tall man (2 yards). Let's say that the top of his head lines up with one dot and his feet line up four dots down. So: (2/4)*1000 = 500 yards away. This same technique can be used to estimate lead on a moving target or to compensate for deflection on a windy day.

The distance from the center of one dot to the center of the next dot is 1 milliradian. We are told (by Leupold) that the length of a dot on one of their reticles is 1/4 milliradian (Given this much information, one can determine that the distance between dots is 3/4 milliradian.).* I use the term "length" because the mil-dot is not round in all cases. It is oblong in some scopes and round in others (Tasco). The width of each dot is an arbitrary distance and is not used for any practical purpose. Like a duplex reticle, the mil-dot reticle is thicker toward the edges and uses thin lines in the middle where the dots are located and the crosshairs cross. The distance between the opposite thick portions is 10 milliradian on Leupold scopes.

*NOTE: 1/4 milliradian = .9" and 3/4 MOA = .785", so, obviously, a mil-dot cannot be both 1/4 milliradian and 3/4 MOA. The maker of the mil-dot reticles for Leupold explains: the dots on their mil-dot reticles are 1/4 mil. They are not 3/4 MOA. Apparently, Leupold just figured that more shooters understand MOA than milliradian, so they just gave a figure (in MOA) that was close, but not super precise.

To use a mil-dot reticle effectively, all one need remember is that the distance between dot centers is 36" at 1000 yards. This lets you determine the range of a target of known size. At that point, you can dial the scope in for proper elevation OR use the dots to hold over the proper amount. The dots on the horizontal crosshair can be used to lead a target (if you know the range to the target, then you'll know the distance between dots, and thus the distance to lead) or to compensate for deflection.

If you own a mil-dot scope or are going to in the future you need to check out this new product called The Mil Dot Master.

Minute-Of-Angle

The term "minute-of-angle" (MOA) is used regularly by target shooters at the range, but is probably understood thoroughly by few (the same goes for mil-dots). Defined loosely, one MOA = 1" @ 100 yards; so, if you shot your rifle 5 times into a 100-yard target and every shot went into a one-inch circle you had drawn on the paper, then your rifle could be said to shoot 1 MOA. Likewise, if every shot goes into a two-inch circle at 200 yards, then you're shooting 1 MOA. A 10-inch group at 500 yards would be 2 MOA.

Now for the fun part. There are 360 degrees in a circle. Each degree can be broken down further into minutes. There are 60 minutes in a degree. Likewise, there are 60 seconds in a minute. Now, to figure out the distance subtended by 1 minute at any particular distance, we need merely to plug those two values into a simple trigonometric equation. The tangent function fits the bill nicely. Here's the equation:

tan(angle) = distance subtended/distance to the target
(units must be consistent--e.g., 1/36 of a yard [1"] divided by 100 yards)

Now, we know the angle (1 minute or 1/60 of a degree) and we know the distance to the target (100 yards), but we need to figure out the actual distance subtended at the target (i.e., is 1 MOA actually 1" @ 100 yards?). What we need to do is solve for "distance subtended." Here's our final equation:

tan(angle)*distance to the target = distance subtended

Make sure your calculator is in "degree" mode (as opposed to "radian" or "gradian") and type in 1/60 (for degrees) and hit the "tangent" button. Then multiply that by 100 yards. This should give you the distance (in yards) subtended at 100 yards. Multiply this by 36 to get inches. The answer should be:

1.047197580733"

This is just a hair over the commonly quoted "one inch." At 1000 yards, this would be almost 10 1/2 inches. Apparently, it is just a coincidence that 1 MOA happens to be REALLY close to 1" @ 100 yards. It is, however, quite convenient.

kuper | March 12, 2011 at 23:00 | Reply

what zoom power do i use and what affects can variating the zoom have

billeboy | March 14, 2011 at 14:42 | Reply

Most scopes with variable zoom have a default setting for use with mildot system. Don't quote me on this, but i think the military uses 10x zoom. If you have a scope, then it would probably say in the user manual.

DAMIEN | April 25, 2011 at 00:29 | Reply

HI WONDERING IF YOU COULD HELP ME IM LOOKING FOR BINOCULARS THAT ZOOM IN AND OUT ELECTRONICLY AND CAN TELL YOU THE DISTANCE OF YOU TARGET (THIS MUST SHOWS UP DIGITALLY IN YOUR BINOCULARS LINE OF SIGHT)
THANKS DAMIEN

Sgt. Rock | April 25, 2011 at 10:21 | Reply

I have had several mil-dot scopes that has had power ranges from 1.5x to 24x power. One should use 10x to determine range on a known size target, but, range can be obtained with any power if one likes additional math. Example: Ranging with a scope set on 5x one takes the reading and muliply by 2 which gives 10x, or using 20x one would divide by 2 and you have it. Simple.

Cpl Thaxton | June 7, 2011 at 14:05 | Reply

Or one could buy a First Focal Plane optic and range on any power he/she would like. Its usaly a good idea to range your target on the highest practicle power as its most accurate to take a mil reading there.

Capt Pete | June 25, 2011 at 08:49 | Reply

It might be worth mentioning a couple more points to do with the mathematical theory.

Firstly the metric system, as used by nearly all militaries, means ranges are in metres rather than yards. The Mildot reticules and metric clicks are more intuitive this way:

1 Mil subtends to 1 Metre at a range of 1000 Metres. Therefore 1/10th of a Mildot (1 click on a Metric turret) = 10cm at 1000 Metres and 1cm at 100 Metres. Very simple maths.

Neither Metric nor MOA are better - although if you use ranges in yards, then MOA makes sense and if using ranges in Metres, mils makes sense. Although it is logical to do so, it is not necessary to match the turret clicks with the reticule as everyone has to learn their system anyway, getting used to the ballistics of their rifle/ammunition and also meteorological effects and gradient etc. The effect of wind, crosswind as well as head or tail wind, will always be the most challenging and unpredictable factor (for longer range shooting).

Also for interests sake only, Pi is 3.14159 (rounded) and is a mathematical constant - the ratio of any circles circumference to it's diameter, which makes if very useful - using 2xPi enables the 1 in 1000 rule (using any units as long as they are the same). A Radian is 2xPi (ie. 6.283 - rounded). Divide this by 1000 to make a decimal version of this number that has useable sized units (ie. Miliradians) and you have 6283 Mils making up a circle. The western militaries found this number not useable enough so traded off a small accuracy sacrifice to round up and make 6400Mils in a circle. The Mils system subtends conveniently into the Military Grid Reference System (based on Universal Transmercator Mapping with 1000M (1KM) grid squares) used by NATO and is used for calculating grid references, bearings, Artillery corrections etc. Military compasses use Mils as do all weapon system platforms (except aircraft and ships who navigate using nautical charts/nautical miles - the system the 360 degree circle was invented for).

Incidentally the Eastern block countries rounded down to 6000Mils in a circle (with arguably simpler maths but unfortunately making the natural fractions of a circle odd numbers). Mildot sights and Metric turrets are nearly always based upon a true mil - 6280 Mils (compared to a 6400 Mils circle the difference is less than 2cm at 1000M).

joey | July 26, 2011 at 20:00 | Reply

May i ask what circle they are talking about? I am trying to get the trig. but what circle are they talking about in the degrees?

brian Ross | August 7, 2011 at 21:46 | Reply

I looked at a 6 inch target on power 21 and did all the math. it came out to that i was 41 yards away when my buddies laser finder said we were exactly 100. How do i calculate the different power zoom into the equation? Thanks.

guitarq359 | August 28, 2011 at 15:21 | Reply

I understand the concept of the mil dots, but I was wondering if there are different methods for variable power scopes. I have a 4 to 16 and zooming in changes the mil reading, which changes the overall range estimation. Do I only read the mils for my 4x (lowest setting)?

CHTexas | August 31, 2011 at 18:42 | Reply

Whether the mil dots will be accurate at more than one power on a variable power scope is dependent on the construction of the scope. If the reticle is in the First Focal Plane, or ahead of the lenses that provide the variable power, they will change size as the power changes, so should give the same results regardless of power. If the reticle stays the same size regardless of the scopes power, or is the Second Focal Plane, then there is only one power where the mil dot size will match what you are looking at. Your user manual should tell you what power the reticle is accurate for, but the quality of scope documentation varies just like the quality of the scopes themselves.

C R | September 25, 2011 at 02:38 | Reply

I could be wrong, but isn't the very first equation wrong? The way it is written it looks as though the range is divide by the height of the target, which is incorrect.

Stev06mm | September 27, 2011 at 23:42 | Reply

I'm am wondering if: 1 Mil subtends 3.6" @ 100yrds then where do the two radius's that meet to form the 1 milliradian angle? Has to be part the plane in which the reticle lies does it not? Ocular lens? The eye of the shooter looking through the scope?

Fritz | November 18, 2011 at 14:59 | Reply

Hallo,

I´m the user of zeiss scope 6-24x56 and I need the information
about the distance between the middle of the crosshair an the bottom edge of the first mildot.
Thanks
Fritz

richard lewandowski | December 13, 2011 at 20:02 | Reply

i am trying to teach myself the use of the mildot and get the concept. bought a mdm have most of it figured out. but i am unsure of once i have the moa correction to my target (say 2.5 moa) my scope a (simmons 44 mag) has 1/4 moa turrets. does this convert to 1/4 moa clicks or 10 clicks to the 2.5 moa to be on target???

rich

Alex | December 15, 2011 at 22:25 | Reply

could you pleas help me to underestand if "1 Mil subtends 3.6" @ 100yrds"so what reading should i have @ 200 ,300,400 yard with 1 mil. to know that when i use the zoom from 100 yard to 200 or 300 the dot are moving apart from eachother, is it still going to be 3.6" for 1 mil! thanks i really need this helpe from export.

Jason | December 29, 2011 at 11:11 | Reply

The thing you guys aren't getting is there are 2 types of focal planes for scopes. the 1st focal plane are better the reticle "grows" as you zoom in so that 1 mil stays 1 mil at any power. Cheeper scopes use a 2nd focal plane in which range estimation only works for a certain power (usually 10x).

Hans | February 19, 2012 at 21:32 | Reply

Since so many of us google our way to information, I thought I
would leave a belated comment to your reply:

You are correct in that a 2nd focal plane reticle is typically found on cheaper scopes, but at high magnification a 1st focal plane reticle can obscure your target. For that reason there are quite a few long-range shooters who prefer the 2nd focal plane reticle.
So...1st focal plane reticles are probably more useful on average, but not necessarily 'better', it just depends on the use. My Nightforce wasn't cheap, believe me ;)

Hans | February 19, 2012 at 21:33 | Reply

Since so many of us google our way to information, I thought I
would leave a belated comment to your reply:

You are correct in that a 2nd focal plane reticle is typically found on cheaper scopes, but at high magnification a 1st focal plane reticle can obscure your target. For that reason there are quite a few long-range shooters who prefer the 2nd focal plane reticle.
So...1st focal plane reticles are probably more useful on average, but not necessarily 'better', it just depends on the use. My Nightforce wasn't cheap, believe me ;)

bc | May 24, 2012 at 10:19 | Reply

Equation at the beginning of the article says: Height of target (yards) X 1,000 = Range (yards)/ Height of target (mils)

which would give:
Height of target (yards) X 1,000 X Height of target (mils)= Range (yards)
Therefore: 2 yd target x 1000 x 2 mil = 4000 yds

I think the equation should be:
Height of target (yards) X 1,000 = Height of target (mils) X Range (yards)

which would then give:
Height of target (yards) X 1,000 / Height of target (mils) = Range (yards)

2 yd target x 1000 / 1 mil = 2000yds

2 yd target x 1000/ 2 mil = 1000yds

2 yd target x 1000/ 4 mil = 500yd

matt | June 6, 2012 at 10:23 | Reply

Ranging in mils is easy. Look thru your scope at a target that is a known 51 inches for example and in your scope it fits one mil. Take 51 add two zeros to the end = 5100 Divide 5100 by 3.6 = 1416.6 yards simple. Most second focal tactical scopes will have a mark on the power ring to set at for ranging. For MOA set a target at 100 yards that has one inch squares. Then adjust your power to fit squares. I have Nightforce MIL and MOA scopes 5.5x22 NXS at 22 power one MIL or one MOA is correct but there is a mark at 11 power that the reticle marks are doubled so that one reticle MOA = 2 MOA or MIL.

sloot | June 14, 2012 at 12:11 | Reply

this site may provide some additional info that can be used to supplement your provided documentation.tks

mike | August 20, 2012 at 23:43 | Reply

would like to know the reticle subtension on a variable power,2nd focal plane.scopes ranging power is 22x and that is where the the lines spacing are 1 moa the variable nxs 12x-42x is used in all magnification.how much difference for reference

Brent Hamborg | December 14, 2012 at 00:37 | Reply

Hey Matt that an interesting formula , I always use the inches of known target x 27.77 / the # of mils. It's a good way to put inches in and get yards out. Learned somthing new tanks

Iver | December 15, 2012 at 08:31 | Reply

Mil Dot reticle. I have one simple queston. What if the object is 1.80 meters tall (180cm) this could be a person or Moose (shoulder high). From what I understand from the formula the reticle will be 'missing' mil dots?? What if the object is only 100 meters away (abt 110 yard) The object will be to big in the scope to be able to use the reticle and the dots to count/measuer the distance? Using all 10 mildots we get to a minimum distanec to target at 180 meters? I would have needed 18 (20) mildots to measure a short distance of 100 meters?? Is mil dot scopes only made for long range shooting above abt 200 yards?

ron stewart | January 3, 2013 at 10:01 | Reply

thanks a lot for the support and imfo! It is a a far better way than the training I received as a usmc rifle range in 1968 the ball at 500 yards looked like a ball pen point on a four foot target.

christopher | March 10, 2013 at 19:42 | Reply

i have 168 gr sierra match king 308 match rounds for a remmington 700 vtr 22in barrel. the scope is an inexpensive 6-24x40 BSA mil dot. Im trying to figure out how to make the long shot. i can hit 300 meters with iron sites. so i want further capabilities and have no idea how. plz help.

Cpl Lucky | April 1, 2013 at 21:49 | Reply

@ Iver If you want to range a target at closer ranges, you use a part of the target. Example; at 300 meters, you could measure a person from the waist to top of their head(0.9 or 1.0m)in mils and then punch the mils and meters into the formula. If the person is too close for that, you could measure their head.

Chris | August 18, 2013 at 14:46 | Reply

Almost every mildot scope will take measurements from it's maximum power. Some night force scopes I noticed that are over 25x are set to take their mil readings at 25x and it's marked on that particular scope so you don't forget in the field. Every manual will tell you which power to set your scope at for taking a mil reading though. But like I said, 90%+ scopes manufactured today will use the maximum power setting.

Lou | November 29, 2013 at 13:00 | Reply

Does anyone know of any fixed 4power scopes that are real mildot in scale?

George | February 26, 2014 at 10:30 | Reply

"MilDot" does not always mean miliradian. Some scope manufacturers (Zeiss for example) distribute scopes with a "MilDot" reticle but the dot spacing at 100 yards is actually less than that - mine is 1.8 inches.
The shooter purchasing a MilDot scope should take the time to do some research before committing to a purchase and, when in doubt, call the manufacturer's customer service center to make certain that what they order is what they expect it to be.

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