This page shows ranging formulas for various reticles and dimensional units. Thanks to Robert Simeone, mathematician and rifleman, for compiling the formulas shown here.
Milliradianbased Reticles
(1) 

Distance to Target(Yards) = 
Height of Target (Yards)
Image Size(mils) 
* 1000 

(2) 

Distance to Target(Yards) = 
Height of Target (Inches)
Image Size(mils) 
* 27.77 

(3) 

Distance to Target(Meters) = 
Height of Target (Inches)
Image Size(mils) 
* 25.4 

(4) 

Distance to Target(Meters) = 
Height of Target (Meters)
Image Size(mils) 
* 1000 

(5) 

Distance to Target(Meters) = 
Height of Target (cm)
Image Size(mils) 
* 10 

Minute of Anglebased Reticles
(6) 

Distance to Target(Yards) = 
Height of Target (inches)
Image Size(MOA) 
* 95.5 

(7) 

Distance to Target(Meters) = 
Height of Target (inches)
Image Size(MOA) 
* 87.3 

(8) 

Distance to Target(Meters) = 
Height of Target (Meters)
Image Size(MOA) 
* 3438 

(9) 

Distance to Target(Meters) = 
Height of Target (cm)
Image Size(MOA) 
* 34.38 

One Inch Per Hundred Yardbased Reticles
(10) 

Distance to Target(Yards) = 
Height of Target (Inches)
Image Size(IPHY) 
* 100 

(11) 

Distance to Target(Meters) = 
Height of Target (Inches)
Image Size(IPHY) 
* 91.44 

(12) 

Distance to Target(Meters) = 
Height of Target (Meters)
Image Size(IPHY) 
* 3600 

(13) 

Distance to Target(Meters) = 
Height of Target (cm)
Image Size(IPHY) 
* 36 

Reprinted with permission of Linden B. (Lindy) Sisk.
The original can be found on Lindy's site here:
http://www.arcanamavens.com/LBSFiles/Shooting/Downloads/Ranging/
© 2007, 2008, 2009 by Linden B. (Lindy) Sisk
Permission is granted to print or photocopy the entire article intact, including this notice. All other rights reserved.
