Open any analyzed position in this tool and you will see a number like +1.2 or -0.5 next to the evaluation bar. That number is the engine's estimate, in pawns, of how good the position is for one side. The plus sign means White is better, the minus means Black is better. Simple enough — until you try to act on it.

What +1.5 actually means

A +1.5 evaluation means the engine thinks White's position is worth about one and a half pawns. This is not a score of material on the board; it is a holistic estimate that includes material, piece activity, king safety, and pawn structure. A player can be down a pawn but have +0.5 because their pieces are far better placed.

The important thing to remember is that this is an estimate, not a prophecy. Engines are exceptionally good at evaluating positions, but they are still searching a limited depth. A +1.5 position is one where a strong player would expect to convert with good play — not one that wins itself.

The bar versus the number

The bar next to the board and the number in the panel are the same evaluation, drawn two ways. The bar is easier to scan while you replay a game: when it swings from your side to their side, something happened. That swing is the single most useful signal in the whole tool. Find the move that caused it and you have found your lesson.

What the engine is bad at

Engine evaluations are great at tactics and short-term pawn structure, and surprisingly unreliable at long-term strategic judgement. A slow, human-style plan that is winning in twenty moves may score about the same as a risky tactical shot that is equal in ten. The engine does not care that one of those is much harder for a human to play.

It also does not care about psychology or time pressure. The evaluation is computed as if both players are perfect. Your opponent in a bullet game is not perfect, and neither are you. Use the number to find the best objective move, then play the move you can actually execute.

Mates and near-mates

When the evaluation shows a mate score, like +M7, the engine means it has found a forced checkmate in seven moves. Take a moment to look at the line, because the practical point is often simpler than the engine's exact sequence. If you have a forced mate, you do not need the prettiest one — you need the one you will not mess up.

Trust it, but stay human

The right way to use Stockfish is as a sparring partner who always tells you the truth and never gets tired. It is the wrong way to let it replace your own thinking. The number tells you what is best. Figuring out why, and how to reach that position in your own games, is still entirely on you.