Average centipawn loss

A centipawn is one hundredth of a pawn, so 100 centipawns equal one pawn of advantage in an engine's evaluation. To find average centipawn loss, the software takes each of your moves, measures how much worse the position became compared with the engine's best move, and averages those losses across the game. A move that keeps the evaluation level adds nothing, while a blunder can add hundreds. Because the mean is pulled hard by single large errors, one terrible move can ruin an otherwise tidy game. It is also affected by the kind of position: calm, closed games tend to produce low numbers, and sharp tactical ones tend to produce high numbers, whatever the quality of play. Different tools compute it slightly differently, for instance in how they treat positions that are already decided. The common mistake is comparing scores between games of very different character. A sensible habit is to track the trend over many games and look at the biggest single losses, which usually show the real lesson.

An engine can tell you what "Average centipawn loss" means for a position, but not which mistakes you keep making; a first lesson with George Li reviews your games and finds those.

Related terms

• Centipawn

  A centipawn is one hundredth of a pawn, the small unit engines use to report evaluations, so a score of 150 centipawns means the engine thinks one side is about one and a half pawns better.

• Accuracy

  Accuracy is a percentage produced by analysis software that summarizes how closely a player's moves matched the engine's preferred choices over a game, with higher numbers meaning fewer costly errors.

• Evaluation

  An evaluation is a numerical judgment of who stands better in a position, usually given in pawns from White’s point of view, where positive favors White and negative favors Black.

• Blunder

  A blunder is a very serious error, such as leaving a piece undefended or missing a decisive tactic, that swings the evaluation so far that a good position turns bad or a bad one becomes lost.

• Game review

  A game review is an automatic engine pass over a finished game that marks each move, shows how the evaluation changed and points out the turning points, mistakes and missed chances.

Guides that go further

• How to choose a chess coach

  What to decide first, the questions to ask, what a first lesson should show and the red flags to avoid.

• How much does chess coaching cost?

  Published rates for private, group and subscription chess coaching, with the source and the date of each.

• The first lesson

  A game review, a read on your level and a written study plan from George Li.