Instructions
Determine the minute of angle (MOA) of your scope dials. This value is commonly marked on the face of the dial; if it is not, consult the manual or contact the manufacturer. Most scopes have an adjustment of 1/4 or 1/8 MOA. Fortunately, MOA measurements conveniently equate to approximately the same measurement in inches at a distance of 100 yards. This information is the basis for calculating scope clicks.
Determine the range of your target in yards, preferably in increments of 100 yards.
Using a scope with a 1/4 MOA at a range of 100 yards as a base line, you would increase the value of each click as your range increases and decrease the value as it decreases. For example at 100 yards, a 1/4 MOA scope will move the point of aim 1/4-inch with a single click. If the range is increased to 200 yards, the value of each click doubles to 1/2-inch; at 300 yards to 3/4-inch and so on. Conversely, if you decrease the distance to 50 yards, your click value would decrease by half to 1/8-inch.