An Elo rating is a single number that estimates a chess player’s strength, calculated from their results so that the gap between two players’ ratings predicts the expected score of a game between them. Higher number, stronger player.
It’s named after Arpad Elo, a Hungarian-American physics professor (so it’s a surname, not an acronym — please don’t write “ELO”). FIDE adopted his system worldwide in 1970, and it’s been the backbone of chess ranking ever since.
The magic is that a rating isn’t just a scoreboard — it’s a prediction. Beat someone much stronger and your number jumps; lose to someone much weaker and it tumbles; do exactly what the gap predicts and it barely moves. How much it swings per game is set by a K-factor (bigger for newcomers, smaller for elite players who’ve already proven their level).
The single most useful thing to know is what a rating gap actually means:
| Rating gap | Favorite’s expected score |
|---|---|
| 0 points | ~50% (a coin flip) |
| 100 points | ~64% |
| 200 points | ~76% |
| 400 points | ~91% (about 10 wins in 11 games) |
So a 400-point edge is enormous — the underdog scores roughly one point out of eleven. FIDE’s official rating list currently has a floor of 1400; online platforms like Chess.com and Lichess use Elo’s smarter cousins (Glicko and Glicko-2), though people still casually call any of these numbers “Elo.”
Related terms
- Deep dive: chess rating systems explained — Elo, Glicko, and the math, in plain English
- FIDE vs Chess.com rating — why your two numbers don’t match
- Chess titles · Grandmaster · FIDE Master
- Back to the chess glossary
Frequently asked questions
Is it “Elo” or “ELO”? “Elo.” It’s the surname of Arpad Elo, not an acronym — capitalizing all three letters is a common mix-up.
What’s a good Elo rating? It depends on your pool. Roughly: under 800 is a brand-new player, 1200–1600 is a solid club amateur, 2000+ is expert, and 2200 and up is master territory. Full breakdown in rating systems explained.
What’s the highest Elo ever? Magnus Carlsen reached a peak FIDE rating of 2882 in 2014 — the highest classical rating in history.
Does my online rating equal my FIDE Elo? No. They’re separate pools that don’t talk to each other, and online ratings usually run higher. We compare them in FIDE vs Chess.com rating.
Written and fact-checked by the Chess Lab Academy Editorial Team (AI-assisted, human-edited) · Rating facts verified against FIDE Rating Regulations and Wikipedia · Last verified 2026-07-13 · Sources · How we verify content.