ARAM is often seen as League of Legends’ casual mode, but its matchmaking system still relies on the same core concept used across all game types: MMR.
Even though ARAM has no ranked ladder or divisions, it still uses an internal metric to try and pair players of roughly equal skill. If you’ve ever wondered why some games feel balanced and others feel like a complete stomp, the answer is mismatched MMR.
HOW MMR DIFFERS FROM ELO
MMR and elo are often talked about interchangeably, but they serve different purposes.
Elo was the original public-facing rating system in League’s early seasons, and it directly represented a player’s rank.
These days, elo is mostly interchangeable with "rank", with high elo literally meaning a high rank (Diamond, Master, Grandmaster, etc). The old elo system was phased out in favor of MMR, with rank being a bit of a "hard cap". Actual matchmaking mostly uses MMR, but even if your MMR is close to somebody else's, you are still limited by rank.
In ARAM, only MMR is used. Since there’s no visible ranking, no promotions or demotions, and no placement matches, the entire matchmaking system depends on your ARAM-specific MMR. This sole number determines the quality of opponents you face. If your ARAM MMR is high, you’ll often be matched with players who perform well in that mode, regardless of their ranked Summoner’s Rift tier.
Over time, MMR in ARAM adjusts to your actual performance. Wins raise it, losses lower it, and the changes are more pronounced when the match outcome differs from what the system expected. For example, beating a team with higher MMR than yours increases your score more than defeating a lower-rated team.
The actual math on how MMR works is completely unknown. It's something often called a "black box algorithm"—we don't know how its logic works specifically, and there's no way to actually know your MMR.
HOW TO CHECK YOUR ARAM MMR
League’s client does not display MMR. Riot has never made this value visible, which means there’s no official way to check it. The best approximation is to use third-party stat trackers. These websites estimate MMR by analyzing your match history, including the visible ranked tiers of your teammates and opponents.
MMR is a complicated topic, which is better explored in our articles around the LoL Ranking System and LoL MMR Checkers. To make a long story short, there are no ways to find out your MMR, but there are ways to approximate it.
If you consistently get matched with high-Platinum or Diamond players in ARAM, that likely means your ARAM MMR is in that range. These tools are not perfectly accurate, but they can give you a rough sense of where you stand. Pay attention to the ranked divisions of players in your matches, especially if your opponents tend to be several tiers higher or lower than your main account’s rank.
Keep in mind that your ARAM MMR is completely separate from your ranked MMR. You could be Gold in solo queue but have a much higher (or lower) hidden MMR in ARAM depending on how often you play it and how well you perform in those games.
With that said, your ARAM MMR does factor in during your ranked placements.
HOW TO INCREASE YOUR ARAM MMR
Since ARAM’s matchmaking is driven purely by wins and losses, the most direct way to raise your MMR is to win more games than you lose.
Start by focusing on champion familiarity. The all-random nature of ARAM means you won’t always get a comfort pick, but you can still prepare by understanding the basic kits and itemization patterns of a broad range of champions. Spend time reading recommended rune pages and builds for champions you rarely play. Use tools like u.gg or OP.GG to check the highest-performing setups for ARAM specifically, since they often differ from what’s usually built.
Positioning, poking and spell usage also play a bigger role in ARAM than most players account for. Champions who can safely deal damage or disengage tend to control the pace of the game. Try to play around your team’s strengths rather than looking for solo plays.
Lastly, learn from outcomes. If a game goes poorly, take ten seconds after the defeat screen to ask yourself why. Did you overextend early and fall behind? Did your team lack frontline and you chose another squishy champion? These micro-decisions impact whether you win or lose, and over time, they shape your MMR. Treat each loss as a data point. Your goal is not to avoid defeat, but to understand it.
DO SKIN BOOSTS AFFECT YOUR CHANCES OF WINNING IN ARAM?
When a player activates a Skin Boost in ARAM, it temporarily unlocks a random skin for every champion on the team for that specific game. Each teammate gets a skin, and the player who initiated the boost receives bonus Blue Essence and a reroll refund.
Skin Boosts do not influence gameplay outcomes. They are a cosmetic feature, and their effects are entirely visual. There's no evidence that points towards having a skin influencing winrate one way or the other.
CONCLUSION
ARAM has no ranked system, but it still uses its own hidden matchmaking rating (MMR) to create balanced games. Unlike Summoner’s Rift, which ties matchmaking partly to visible rank, ARAM relies entirely on this invisible metric.
MMR increases or decreases based on your performance, and depending on how likely your wins are.
These estimates are rough but can give a general sense of your standing. Winning consistently, understanding champion kits, and improving decision-making are the most reliable ways to raise your ARAM MMR.
