php game, formula to calculate a level based on exp

Question

Im making a browser based PHP game and in my database for the players it has a record of that players total EXP or experience.

What i need is a formula to translate

Answer 1

If you wanted the following:

• Level 1 @ 0 points
• Level 2 @ 50 points
• Level 3 @ 150 points
• Level 4 @ 300 points
• Level 5 @ 500 points etc.

An equation relating experience (X) with level (L) is:

X = 25 * L * L - 25 * L

To calculate the level for a given experience use the quadratic equation to get:

L = (25 + sqrt(25 * 25 - 4 * 25 * (-X) ))/ (2 * 25)

This simplifies to:

L = (25 + sqrt(625 + 100 * X)) / 50

Then round down using the floor function to get your final formula:

L = floor(25 + sqrt(625 + 100 * X)) / 50

Where L is the level, and X is the experience points