Explainer
What is Elo?
Elo is a way to measure the relative skill of competitors from nothing but their results. It was invented for chess by Arpad Elo, a Hungarian-American physics professor, and it works just as well for League of Legends teams.
How it works
Every team carries a single number — its rating. When two teams play, their ratings set an expectation for who should win and by how much.
The winner takes points from the loser. How many depends on the gap between them: beat a team you were supposed to beat and you gain a little; pull off an upset and you gain a lot. Over many games, ratings settle into a ranking that reflects how teams actually perform against each other.
Why we use it
A single rating makes teams directly comparable — across leagues, across regions, and across time. You can watch a roster climb through a split, or line up two teams that have never met and get a sense of who has the edge.
For all its simplicity, Elo is surprisingly good at predicting outcomes — which is what makes it a useful lens on pro play.
Curious what a rating gap is actually worth? Try the Elo win-probability calculator.