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Convert from MIL or MOA to distance

Level: Basic

Instrument: Wndsn MIL/MOA Calculator

The Wndsn MIL/MOA Distance Calculator (MMC) is an instrument for measuring distances. It avoids mental arithmetic errors under stress and allows distances to be determined precisely from two input values without having to guess. You simply enter MIL or MOA as measured on the reticle and determine the distance to the target by aligning the string to the known size.

Figure 1. Wndsn MIL/MOA Distance Calculator: Instructions.

Figure 1. Wndsn MIL/MOA Distance Calculator: Instructions.


The target measured is 5 MIL or 17 MOA tall; the known height of the torso is 1 m; we read on the D scale a distance of 200 m (Figure 1).

  1. We align the string to the MIL value measured with the reticle. (Ex.: 5 MIL, alternatively 17 MOA)
  2. Then we align the free end of the string with the known size of the target (unit of choice) on the S scale.
  3. Finally, where the string crosses the D scale, we read the distance (same unit as the size).


Note that you can measure in any unit (cm, in, ft) or system (metric, imperial, custom), the factors are always the same and return your distance in the same unit you used to approximate the object measured.


  1. Torso height: 1 m; we read on the D scale a distance of 200 m.
  2. Torso height: 1 yd; we read on the D scale a distance of 200 yd.
  3. Torso height: 3 ft; we read on the D scale a distance of 600 ft.


Accuracy is determined by two elements:

  1. The reading of the scale and approximation of the corresponding mark
  2. The estimation of the height of the measured object

For training and reference purposes, you may want to create a table of the exact height of common objects.

Scale jumps

For measurements that are outside the scale values, or to shift calculations to scale ranges with finer logarithmic divisions, it is possible to move the decimal point or to achieve greater precision by multiplying[1] (jumping scales). This means that if a value does not fit on a scale (right or left), divide or multiply it by any number and multiply or divide the result back by the same number.


Known target size: 30 cm; measured as: 0.5 MIL.

  1. We multiply 0.5 MIL by 10 and place the string at 5 MIL.
  2. Then we divide the 30 by 10 and pull the string through the 3 on the S scale.
  3. The result on the D scale is 600, which we need to multiply by 10 twice for a final result of 60,000 cm or 600 m[2].


Q: Can I measure the width instead of the height of an object?

You can measure any dimension; width, height, etc., as long as it's on a plane that is perpendicular to you, the trigonometry doesn't care where in space the triangle is located.

Q: My target is measured in inches?

If the target size is in inches, we use the inner, left hand S scale, which is graduated as 3 feet divided in 12 inches each. Inputting inches this way, the resulting value on the D scale is in feet (and divided by 3, we have yards).

See also:


  1. Scale jumps 
  2. Control 

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