MMR (also known as Match Making Rate or Elo) is a hidden statistic / value in League of Legeds on which the game matches you with opponents and teammates. For every league and division (e.g. Gold 4) there is an average MMR. If your MMR equals the average you will most likely get matched with players that are in the same league & division as you.
For example, if you are currently Gold 3 and you get matched with Diamond tier players this means that your MMR/ELO is way higher than it should be. Therefore you will gain a lot more LP than you lose (e.g. +30LP and -12LP). You are also much more likely to skip divisions or promo games.
More useful information can be found on: https://leagueoflegends.fandom.com/wiki/League_system
The Rank #1 Player on EUW server is TheUnshackIedone with Challenger 1408LP and a MMR of 2801. On NA server it currently is the player Santorin with 1579 LP and a MMR of approximately 2770. (last update on 23.11.2019)
We kept it really simple. Just enter your League of Legends summoner name of your account and click the 'check my MMR' button. The page will automatically reload and show your estimated MMR score. Please notice that this calculator is still in early BETA stage, which means that certain errors could occur. If you find any exploits or bugs feel free to contact us via following e-mail: firstname.lastname@example.org
Yes! Your summoner has a different MMR value for every gamemode. This checking tool does also analyze your normal games and even your ARAM games and provides you an estimated number.