To keep it simple according to the Leupold literature Four clicks = 1 inch at 100 yards, 1 MOA is 1.047 inches at 100 yds. So 4 clicks is approximately 1 MOA.
1 MOA is 1/60 of 1 degree. One must remmember that 1 inche per hundred yards (IPHY) and MOA are not one and the same for long range shooting. 20 IPHY at 1000 yards accounts for 200 inches of elevation correction. 20 MOA accounts for 209.44 inches of elevation correction at 1000 yards.
IPHY & MOA should not be confussed