How much is 70 mph pitch in little league is equivalent to MLB?

I don't know exactly but I've watched the Little League World Series enough and they always refer to Little Leaguers pitching speed in relation to MLB and I believe that 70 mph Little League would be around 100 mph MLB A 70 mph little league pitch is equivalent to about a 111 mph MLB pitch. (This is calculated based on an average little league pitch at 57.5 mph and an average MLB pitch at 91 mph.)