Right progress bar max/min values

I got an problem with tag, it makes the progress bar right, but i cant calculate right values to make that display from start to the end of bar. e.g.: that a game. I got 2431375 EXP, to next level i need 2438402 EXP. EXP never resets to zero, that mean if i reached new lvl, exp will continue counting from 2438402. So, i have not idea to display it right. Progress bar of exp is always almost in end, however i tried to calculate some values. Someone got ideas?(btw: all i got is only exp/required exp, no any values else)