Your question is not clear.
Did you mean maximum 529 distribution (withdrawal)? That not only depends on how much expenses you have (tuition, fees, books, a computer, room & board) but also on how much scholarship you have and whether you are eligible for a tuition credit and which credit.
There are three things you can do with your Qualified educational expenses (QEE):
- Allocate then to scholarships (so that the scholarship remains tax free)
- Use them to claim an education credit
- Allocate them to the 529 distribution (1099-Q) so that it will not all be taxable
