I'm sorry, I don't want to be a smart ass, but were you looking for these?
The formula:
1: (your level)² * 5 = total xp needed for new level.
Which leaves the needed xp for each new level for this formula:
2: [(next higher level * 10) - 15] = xp needed for new level.
Gained health can be calculated through this:
3: (new level * 5) - 5 = extra hp gained