How to calculate the level relative to experience?

Question

Game development

Hello. There is experience in the game. On the passage of each level you need op. count experience.
For example, there are 10 experience.
3 exp == 2lv
6 exp == 3lv
9 exp == 4lv
10 exp == displays how much experience is left to 5lv.
There was an idea to do this: I
earned 3 experiences. We update the experience by 0, and in lv we write 2lv.
Then I earned 6 experience, we update the lvl by 3 and reset the experience.
But I think I'm doing something wrong :)
Thanks in advance :)

Answer 1

It is convenient to specify a one-to-one correspondence between experience and lv by the function .
PS please change the word "count" to something less weird.