Leveling up means not as leveling up the account level or ranking up but the "ingame" leveling up of the character. Most of the time I play LOL I noticed that despite having higher creep score than my opponent I am still underlevel. So it is certainly not the CS.
Is it the damage dealt to champion that determines leveling up a champ?
Sorry but I didn't find it anywhere else with my search tags.
Best Answer
Leveling up is based on being in range of the creep when it dies. You do not need to last hit it, as experience from minion deaths is split between all champions within 1400 range.
However, there are a number of reasons why they might be leveling faster than you: