LP and MMR in LoL: why you gain +18 and lose -25

LP: what you see

LP, or league points, are the visible counter of your division. Each division goes from 0 to 100 LP. When you pass 100, you move to the next division: Iron IV, then Iron III, Iron II, Iron I, then Bronze IV, and so on up to Diamond I. Above that, Master and the following tiers have no divisions.

LP do not measure your level. They measure your progress inside the division you are in. That distinction matters for everything that follows.

MMR: what you do not see

MMR, for matchmaking rating, is the hidden rating the game computes for every player. It serves two purposes: building balanced games, and deciding how many LP you gain or lose each time.

Your MMR goes up when you win and down when you lose, but it is shown nowhere. You can only guess it, from your LP gains and the rank of your opponents.

Why your gains are asymmetric

The game compares your MMR to your displayed rank. If they are aligned, your gains and losses are roughly equal. If your MMR is above your rank, the game pushes you up: you gain more LP per win than you lose per loss. If your MMR is below your rank, it is the other way around.

Gaining 18 and losing 25 is therefore the sign that the game considers you a bit lower than your displayed rank. It happens after a losing streak, after a rough season, or when a rank was reached partly thanks to teammates. Nothing personal: it is a formula.

How it corrects itself

There is only one way to bring an MMR back up: winning games. Each win raises it a little, and when it gets back to the level of your rank, your gains become symmetric again. No trick, no champion or role change gets around that.

The trap is impatience. An MMR below your rank corrects itself over time, not in one evening. If you chain games angry to catch up, you lose more and widen the gap. Play less, play better, and let the formula do its work.

• Winning raises MMR, point by point.
• Gains become symmetric again when MMR catches up with the rank.
• How long it takes depends on the starting gap and your win rate.

Tiers, promotions and demotion

Going from Iron I to Bronze IV means changing tier. In the current system, promotion happens by passing 100 LP in division I of the tier, with no qualification series. Conversely, dropping below 0 LP in division IV of a tier can demote you to the previous tier.

After a tier promotion, the game protects you for a while against immediate demotion: you do not drop back at the first loss. That protection is limited in time and in effect, and the exact rules evolve from season to season. Keep the principle: a recent promotion is not lost at once, but it does not hold on its own either.

What a boost or a duo changes, and does not

A boost or a duo wins games on your account, so it raises both your LP and your MMR. At the end, you are at the target rank with an MMR that followed, since the wins were real. What neither of them changes: the formula. Once the service is over, your own games decide your gains.

If your level is below the rank reached, your MMR will come back down with your losses, and your gains will become asymmetric again. That is why duo, where you play yourself and improve, holds up better over time than a rank obtained without you. And that is why we never promise that a rank stays yours. One more difference between the two: solo boosting goes against Riot's rules, as our terms of sale state, while the duo queue is part of the game.