What is MMR and ELO in League of Legends?

mmr and elo

I’d like to discuss about what exactly is MMR and ELO. MMR is the short for Match Making Rating.  There are two important keywords, “Match Making” and “Rating”.  No one exactly know what the formula is except for Riot themselves, but Riot games has given an important hints in their previous post (https://support.riotgames.com/hc/en-us/articles/201752954-Matchmaking-Guide) and that is

  1. Cumulative Win/Lose of matches you had previously are part of the factor
  2. KDA (also called Kill Death Assist Ratio) are not part of it.

But first, lets step back a little bit, and figure out what actually happens when you initiate a queue in the League system.

Match Making System

So say, you’re doing a solo queue, you just “Launch” a Ranked games and time elapses ticks. While waiting for your games to be found, beneath all this, a search query initiated in Riot games Match Making Server and as it placed you in the waiting pool. Lets imagine that you are in a waiting Lobby and Match Making as the Lobbyist. There are several people in the same lobby as you are . The Lobbyist has one task: Find 10 people. Now, what she has to do is to compare people in the entire lobby with similar skills as you; most likely a division or two division higher/lower. One by one she tries to fill up the slots as she finds them. Once the slots are filled up, you’re game is found.


These methods creates sort a balance game so both teams has a good chance of winning, well most of the time.. So, in order for Matchmaking to identify your skills, it has to tagged you with a score. And this score will determine your strength as a player so it could match you with other people with roughly similar skills. That score my friend, is your MMR. And… it is totally hidden from you, hidden behind your League and League points. Although, league points is a different scale entirely ( I will add another post for that topic). MMR is also tangibly called hidden Elo.

Elo rating system

Elo, also called Elo rating system, are used hands in hand with MMR are basically the same thing. It is used in  player vs player games like chess, and it is in basic term, a method to calculate a relative skill level of a player.

A player’s Elo rating is represented by a number which increases or decreases depending on the outcome of games between rated players. After every game, the winning player takes points from the losing one. The difference between the ratings of the winner and loser determines the total number of points gained or lost after a game. In a series of games between a high-rated player and a low-rated player, the high-rated player is expected to score more wins. If the high-rated player wins, then only a few rating points will be taken from the low-rated player. However, if the lower rated player scores an upset win, many rating points will be transferred. The lower rated player will also gain a few points from the higher rated player in the event of a draw. This means that this rating system is self-correcting. A player whose rating is too low should, in the long run, do better than the rating system predicts, and thus gain rating points until the rating reflects their true playing strength. – Source: (Wikipedia: Elo rating system)

As the descriptions suggest, it creates a zero sum game, where a person points are transferable. Rumors says, the score every player with is at 1200 Elo points. As you play more games, you will start to gain and lose your points. With such environment, every region will ends up having a normal distributions of player skills. With Bronze league on left side of the spectrum (below) and Challenger on the right side of the spectrum.


Relativity of skills level

It is also important to emphasized the words relative as it scales you only to the people in the same League and Server. A guy with Platinum Tier in NA server might not be similar to the guy of the same Tier in OCE or KR. They are just not comparable, unless the score system normalized between the two server. Although, as I mentioned before, no one knows whats the algorithm for MMR, either the are very similar to chess Elo system or not, but the concept are comparable.



  • MMR is Match Making rating used to calculate relative skills of a player
  • Hidden ELO = MMR.
  • MMR is not equal to League points.
  • MMR is a relative scoring system