Mil dot ranging calculator
Quick answer: divide a known target dimension by the mils it covers in your reticle to get the distance. Distance in yards equals 27.78 times the target size in inches divided by mils, so an 18 inch dimension that fills 2 mils is 250 yards away. In metric it is cleaner still: distance in meters equals 10 times the size in centimeters divided by mils, because one mil covers exactly 10 cm at 100 m. For an MOA reticle the constant is 95.49 instead of 27.78. Enter your numbers below.
Estimate the distance
Turn on JavaScript for the live result. The reference table and worked example below give you the same math by hand.
Ranging with a reticle is the inverse of asking how much of a target a mark covers. If you want that direction instead, use the dot size at distance calculator, and for turret clicks see the MOA/MRAD adjustment calculator.
Mil ranging reference table
Distance in yards for a known dimension against a mil reading, from 27.78 times the size in inches divided by mils. This is the same arithmetic the calculator runs.
| Known size | 1 mil | 2 mils | 3 mils | 4 mils |
|---|---|---|---|---|
| 10 in | 278 yd | 139 yd | 93 yd | 69 yd |
| 18 in | 500 yd | 250 yd | 167 yd | 125 yd |
| 20 in | 556 yd | 278 yd | 185 yd | 139 yd |
| 30 in | 833 yd | 417 yd | 278 yd | 208 yd |
Metric is easier to do in your head: one mil covers exactly 10 cm at 100 m, so a 45 cm dimension spanning 2 mils is 225 meters away. The mil system is built for this, which is the practical reason ranging reticles are usually milliradian rather than MOA. See MOA vs MRAD for how the two units compare.
Worked example (do it by hand)
Say you know a dimension on the target is 18 inches and it spans 2 mils between the reticle marks. Distance equals 27.78 times 18 divided by 2, which is 250 yards. Read the same target at 3 mils and it is 27.78 times 18 divided by 3, about 167 yards. With an MOA reticle and a 4 MOA reading, swap the constant: 95.49 times 18 divided by 4 is about 430 yards.
Notice what a misread costs. Calling that 2 mil target 2.2 mils instead moves the answer from 250 to about 227 yards, a 23 yard error from a reading slip you can barely see. Error grows with distance, which is why reticle ranging is a field estimate and a laser rangefinder is the tool when the number has to be right.
The focal plane trap
The formula assumes the marks in your reticle represent the angle they claim. On a second focal plane scope that is only true at one magnification, normally maximum power, because the reticle stays the same visual size while the image zooms around it. Range at 6x on a scope calibrated at 12x and the arithmetic returns a confidently wrong number with no warning. On a first focal plane scope the reticle grows and shrinks with the image, so the marks hold their angular value everywhere in the zoom range. This is the practical reason ranging and holdover shooters pay for FFP: see FFP vs SFP for the full comparison, and best long range rifle scopes for optics that carry a first focal plane ranging reticle.
FAQ
How do you range a target with a mil dot reticle?
Measure how many mils the target covers in the reticle, then divide a known dimension by that reading. A milliradian subtends one thousandth of the distance, so distance equals target size times 1000 divided by mils, in the same unit. Working in inches and yards the shortcut is 27.78 times the size in inches divided by mils. An 18 inch dimension that fills 2 mils is 250 yards away.
What is the mil ranging formula in yards?
Distance in yards equals 27.78 times the target size in inches divided by the reading in mils. The 27.78 comes from 1000 divided by 36, which converts the raw milliradian answer from inches to yards. In metric it is simpler: distance in meters equals 10 times the target size in centimeters divided by mils, because one mil covers exactly 10 cm at 100 m.
Can you range a target with an MOA reticle?
Yes, only the constant changes. There are 3437.75 arcminutes in a radian, so distance equals 3437.75 times the target size divided by the MOA reading, in the same unit. In inches and yards that becomes 95.49 times the size in inches divided by MOA. An 18 inch dimension covering 4 MOA sits about 430 yards away. MOA reticles are less common for ranging because the arithmetic is uglier than the mil version.
Does reticle ranging work on a second focal plane scope?
Only at the magnification the reticle was calibrated for, which is usually maximum power. On a second focal plane scope the reticle stays the same visual size while the image zooms, so the marks represent a different angle at every other setting and the formula silently returns the wrong distance. On a first focal plane scope the reticle scales with the image, so the marks hold their value at any magnification and ranging works throughout the zoom range.
How accurate is ranging with a reticle?
It is an estimate, and its error is dominated by two things you control. The first is how well you actually know the target dimension, since the answer is directly proportional to it. The second is reading resolution: at long range a small misread of the mil value moves the answer a long way, because distance is inversely proportional to the reading. Treat it as a field approximation and use a laser rangefinder when the shot demands a real number.
Related: MOA vs MRAD · MOA/MRAD adjustment calculator · dot size at distance calculator · FFP vs SFP · best hunting rangefinders.