Plychess
Engines

Stockfish Depth, Evaluation, and PV Explained

Feb 16, 2026
8 min read

Depth

Depth is how far the engine searched (in plies). It’s not a guarantee of correctness. Engines search unevenly: forcing lines go deeper.

Evaluation (centipawns)

+0.50 is roughly half a pawn advantage. It’s a heuristic score. Learn trends: if your move drops the eval from +0.8 to -1.2, you blundered.

PV (principal variation)

PV is the current best line the engine expects. It’s useful for learning tactical refutations and defensive resources.

Use the tool

Paste your raw output here: Stockfish Output Explainer

Want the bigger picture? How chess engines work