The number of clicks (or divisions) per MOA (minutes-of-angle) varies depending on the make and model of the scope. Many scopes have four clicks per MOA, but a large number of scopes have only one and two clicks per MOA. And a few scopes have as many as eight clicks per MOA. Check your scope's literature to find out how many clicks it has per MOA.
If you can't find any literature for your scope, you can still measure the number of clicks per MOA it has. To make this measurement, you need a gun rest or some other way of preventing the scope from moving while you turn the elevation adjustment knob. However, the scope doesn't have to be mounted to the gun.
On a target, draw two straight horizontal lines exactly one inch apart. The lines must be parallel to each other. Place this target exactly 20 yards down range. Adjust the mounting device and/or scope to get the scope's horizontal hair aimed at the top line on the target. Now, carefully turn the scope's elevation knob in the up (positive) direction until the horizontal hair is aiming at the bottom line on the target (yes, turning the knob in the up direction causes the cross hair to move down on the target). While turning the knob, you need to keep track of how many clicks it's turned. One inch of change at 20 yards is equal to five MOA, so divide the number of clicks by five. The result is the number of clicks your scope has per MOA.
On scopes having four clicks per MOA, turning the scope's vertical adjustment one click in the up (positive) direction adds 0.25 MOA to the sight adjustment and raises the bullet's impact point by 0.26 inch at 100 yards.