Experience (champion)

Champion experience is the way the champions level up periodically. This allows them access to new abilities or higher ranks of existing abilities. Also many base stats and some runes scale as your champion levels up.

Gaining experience
There are only five ways to gain experience. Experience isn't gained over time.
 * Killing a champion: Gives 50% of the experience required to reach the slain champion's next level (not current level). This is increased/lowered by 7% per level difference if the target is higher/lower level and can't be lower than 20%.
 * Assisting: The experience granted for killing, including this increase (see above), is divided equally if there were assistants.
 * Proximity to a minion death: Regardless of whether it was last hit or killed by another source.
 * Structures (except outer turret and nexus): Inhibitors and turrets grant XP, except outer, different ones grant different amounts.
 * Monsters: Different monsters give different amounts. If the killer is of a low level (not compared to the monster) it's upped by 50%. If an ally is within 400 range the XP is split.

Jungle camps

 * See Jungling.

Increasing experience gain
Note that experience gain modifiers stack additively.

Champion abilities

 * A non-displayed passive that used to possess prior to her rework granted 5 experience points every 5 seconds to nearby allied champions that had a lower level than her.

Runes

 * runes increases experience gains by 2% per rune.

Neutral buffs

 * Crystal Scar's Aura grants every champion passive experience gain while playing on the Dominion game mode. (7.2 exp points per second.)

Sharing experience
In addition, when more than 1 champion is sharing experience, 30.4% extra experience is split among all champions.
 * Two champions each gain 65.2%
 * Three champions each gain 43.46%
 * Four champions each gain 32.6%
 * Five champions each gain 26.08%

Experience needed to level up
Summoner's Rift= The following describes the amount of experience required to go from one level to the next on Summoner's Rift.

Minion waves calculations assumes a Summoner's Rift lane, no increased experience sources, no neutral monsters are slain and one champion is in 1600 range of every opposing minion death in said lane. Twisted Treeline = The following describes the amount of experience required to go from one level to the next on Twisted Treeline.

The Crystal Scar has its own experience requirements, which are not exactly but are close to 75% of the values on Summoner's Rift.