In R6, “Elo” usually means your hidden skill rating or MMR, which goes up when you win and down when you lose. In Rainbow Six Siege, players often use “Elo” as a general term even though the game’s ranking system is actually based on a TrueSkill-style matchmaking rating, not classic chess Elo.

What it means

  • It is a number tied to your skill level.
  • Matchmaking uses it to find players around your level.
  • Winning against stronger opponents usually helps more than beating weaker ones.

Why players care

  • It affects who you get matched with.
  • It can explain why some wins give more rank progress than others.
  • People sometimes say “I lost Elo” when they really mean their hidden rating or MMR dropped.

Simple example

If you beat a team that the system thinks is stronger than yours, your rating may rise more. If you lose to a weaker team, you may lose more. That’s the basic idea behind Elo-style ranking.

TL;DR: In R6, Elo is the skill number behind matchmaking and rank progress, even if Siege doesn’t use pure Elo in the strict chess sense.