About TrueElo

TrueElo is a chess analysis site for competitive players. It answers one question an engine will not: not what the best move is under perfect play, but what actually wins for a player at your rating.

A chess engine evaluates a position by assuming both sides play near-perfectly. Below master level nobody does. So an engine can call a position winning that club players routinely fail to convert, and call another one losing that they win more often than not. The gap between those two answers is the thing this site measures.

Where the numbers come from

Every practical number on this site is built from two sources. The first is the Lichess Open Database — hundreds of millions of real, rated games that Lichess releases into the public domain under CC0. The second is Stockfish, which runs in your browser and supplies the theoretical evaluation.

TrueElo does not own the games. It owns the analysis: the filtering by rating bracket and time control, and the Bayesian combination that turns raw outcomes into an estimate you can act on. Cite it as “TrueElo analysis of Lichess data”.

How the True Score is built

Raw win rates lie when the sample is small. A move that won 60% of fifty games is a weaker claim than one that won 55% of five thousand, and treating them alike produces confident nonsense.

So TrueElo starts from Stockfish’s evaluation as a prior and updates it with the games actually played at your rating. Where there is little evidence the engine’s view dominates; as games accumulate, the evidence takes over. What comes out is the True Score — the practical winning chance for a player at your level — alongside the Theory Score, which is what the engine thought. Both are always shown, because their disagreement is the entire point.

Moves are ranked by the lower bound of their uncertainty range rather than by their headline number, so a thinly-evidenced move cannot outrank a well-evidenced one on noise alone.

What it costs

Nothing. There is no subscription and no premium tier. Signing in with a free Lichess account is what lets every number be tuned to your rating and time control; TrueElo reads your username and ratings and never posts to your account. You do not have to play there — a Lichess account works even if your games are on chess.com.

Who runs it

TrueElo is built and run by Aviram Kofman. Questions, corrections, and bug reports are welcome on the contact page.

See also the privacy policy and the terms of use.