Starting Season 3 Riot changed the way ranked system works and changed divisions (I-V) within rating tiers (Bronze, Silver, etc.), and added LP (League Points). The only thing that remained the same (at least according to them) is the Elo system which is now labeled as MMR: Matchmaking Rank and is no longer shown to players.
This article will attempt to explain some of the questions that I see asked frequently, which will hopefully ease your frustration with the system.
Elo or MMR
The Elo system was originally developed for chess players and the point of it is to give each player a numerical rating corresponding to their skill level. As a result players are matched against other players of similar skill levels and given a certain “expected” chance to win or lose. If a lower-rated player wins against a higher-rated one then his Elo gain would be higher than that of a higher rated player winning against a lower rated one.
In a team game like League of Legends it gets a bit more complex as you have to calculate not only individual player’s Elo ratings but also their combined or average rating across two teams. The result is a calculated win percentage of each team and after the match MMR and LP values are adjusted accordingly.
Elo in Season 2
Back in Season 2 things were a lot simpler. You had a certain Elo rating (which was shown on your profile) and for each ranked tier a specific Elo value was required. The exact Elo ratings and corresponding ranked tiers are displayed below (taken from official site):
As you can see you needed 1150 Elo for Silver, 1500 for Gold, 1850 for Platinum and 2200 for Diamond.
Elo in Season 3
There hasn’t been any changes since to how Elo works since Season 2 and we can assume the same Elo numbers are required to reach tiers in Season 3 as well, except now your Elo rating is completely hidden and translated into Divisions.
Behind all the PR crap Riot told us out about the new rating system back at the end of Season 2, the point of the implementation was obvious then just as it is now: you need to play way more matches to achieve the same Elo rating than before. We no longer have a direct knowledge of our Elo rating and there may be all kinds of calculations behind the scenes to make sure your promotion series is tough to go through.
League Points (LP)
To give you a simplistic example with fabricated numbers, say Blue Team has an average Elo (MMR) of 1500, while the Purple Team has an average Elo of 1400. The chances of Blue Team winning over Purple team are 55% based on MMR alone therefore if they win they will gain for example +10 LP and +5 MMR. On the other hand if Purple Team wins, since they are considered less skilled they will gain more LP (+15 LP ) and MMR (+25) for a win. This is why you see a discrepancy in League Points gain or lose, as the gains and losses are directly tied to your MMR.
Do note again that the numbers above are completely arbitrary and serve only as an example.
League Points are basically just a visual representation of your progress and have no bearing on your MMR (it’s the other way around). LP is in no way an equivalent to MMR, and losing -20 LP does NOT mean you also lose -20 MMR. Therefore if for example you are in Silver III and both lose and gain +15 LP for wins and losses then your MMR is considered equal to your skill level and you are in the division you belong in. If you start seeing a difference between LP gains/losses then the system is attempting to place you in the division equal to your MMR, which may be higher or lower than your current one.
MMR in Normal games
In Normal games regardless of maps the MMR works exactly the same way as it does in Ranked. Obviously there are no divisions or tiers to display your skill level but you are match-made with other player in the same way as you would in Ranked.
How to raise your MMR
There is only one guaranteed way to keep raising your MMR rating, and that is by winning more matches than losing. Try to keep your win rate at 55% or above and you will see progress. If your win rate is below 50% then obviously you can’t progress to higher Leagues or divisions. And that is basically all you need to know about Leagues, tiers, divisions, LP, MMR, Elo. You cannot game the system; you need to win more than lose.
Even a 51% win rate could theoretically get you to Diamond, it would just take an unreasonable amount of matches played (as in several thousands). Win rate is however only but a part of dozens of factors the game uses to determine your skill level/MMR, but it is the most important one. Despite its flaws, matchmaking and MMR work well.
TLDR
MMR (old Elo rating) determines how much LP you gain or lose. If your MMR is less than what your division or tier requires you will receive less LP for each win and lose more for every loss, until it gets to the point where your MMR corresponds your division. Instead of being transparent about the system that impacts every match you play Riot is attempting to make it even more complex and disguise it in various ways, resulting in everyone’s frustration. You can basically only increase your MMR and progress to a higher division by winning more than you lose.
If you have any additional questions I’ll be happy to reply so shoot them in the comments below!