How it works
Glimmer Index rates AI models against a fixed ladder of Stockfish opponents. You play the same ladder here, so your rating lands on the same scale as theirs.
- Rated picks the opponent nearest your estimate and alternates your colour, as the benchmark does. No take backs.
- Casual is any opponent, with take backs and no rating change.
- Rated Chess960 game k starts where every model's game k started. Castle by moving the king onto the rook.
- Drag a piece, or tap it and then a square. Keyboard: arrows move, Enter picks up and drops.
How far to trust it
It's an estimate, provisional under ten games. You can think as long as you like, while a model answers each move in one request without a board. Your opponents are Stockfish 19 Lite, running in this browser. Glimmer's are Stockfish 18 on a server, so the rungs are close but not identical. The scale is Glimmer's own, anchored to Stockfish's strength settings, not FIDE or an online site.
Engine: Stockfish.js 19.0.1, lite and single-threaded, built from Stockfish 19, GPLv3. It downloads once, under 2 MB, when your first game starts. Pieces drawn for Crest Arcade.