What the number means
A chess engine shows a single number, like +1.5 or -0.8, that estimates who is better and by how much. Positive favours White, negative favours Black. The unit is the pawn: +1.0 means White is ahead by roughly the value of one pawn, even if no pawn has actually been won — it can mean better activity, king safety or structure worth about a pawn.
Centipawns
Engines measure in centipawns, where 100 centipawns = 1 pawn. So +50 centipawns is +0.5, half a pawn's worth of advantage. This fine resolution is why an engine can tell two very similar moves apart.
A rough guide to the numbers
- 0.0 to ±0.5: equal — the game is a fight.
- ±0.5 to ±1.5: a real but small edge.
- ±1.5 to ±3: a serious advantage; often a won game at club level.
- ±3 and up: usually decisive.
- #3 (or M3): forced mate in three moves — the evaluation switches from pawns to a mate count.
How to actually use it
Do not just read the number — watch how it changes. A sudden jump from +0.3 to -2.0 marks the exact move something went wrong, which is the move worth studying. Set up positions on the analysis board to watch the evaluation move as you try ideas, and use game analysis to find the swings in your own games. To learn how those swings become an accuracy score, read What Is Accuracy in Chess?