That depends on the speed of the swing. For example, if the batter justs bunts at the ball, the difference would only be a few feet!
However, for a full swing and very roughly speaking, the batted ball speed is equal to the bat speed plus 1/2 of the pitch speed. Again, that's a rough estimate. So the difference might be around 40mph. We can get an idea of how much the distance difference is by comparing it to long toss. I guess 40mph would translate to a difference of 100-130 feet.
I suppose that most players can make more solid contact off the tee, so the typical difference may be less.