My Daisy Powerline and Crosman 4x32 scopes are marked "1 click=1/4" at 100 yards". At other ranges, it's proportional... 1/4" at 100 yards = 1/8" at 50 yards or 1/2" at 200 yards. At 25 yards, each click would be 25/100 x 1/4" or 1/16".
But you HAVE to know the baseline increments for the scope. I suspect that 1/4"/100 yards is not uncommon, but I really doubt that it's universal.