Claude Haiku 5.5
Anthropic · released 2026-10-07 · route claude-haiku-5-5 · Model profile
Opening gap: +59 (95%: -170 to +288). The interval includes zero, so we can't yet say whether it performs differently across the variants.
Standard
- Rating
- 1,14595%: 980 to 1,309
- Record
- 12 won, 0 drawn, 12 lost of 24
- Accuracy (open positions)
- 82.7
- Accuracy (all moves)
- 86.5
- Average centipawn loss
- 80
- Blunders / mistakes / inaccuracies per 100 moves
- 7.2 / 4.5 / 8.9
- Matched Stockfish's first choice
- 33%
- In Stockfish's top three
- 57%
- Legal on the first try
- 97.2%
- Illegal / invalid
- 20 of 737 answers
- Forfeits
- 0
- Adjudicated games
- 17
- API-equivalent cost per game
- $0.041
- API-equivalent cost per move
- $0.0014
- Seconds per move
- 13.5
- Model minutes per game
- 6.7
- Tokens per move (in / out)
- 992 / 2,355
- Reasoning tokens per move
- 2,264
- Aborted on our side (not counted)
- 1
By phase
| Phase | Moves | Accuracy | Centipawn loss | Blunders /100 | Engine match |
|---|---|---|---|---|---|
| Opening | 240 | 87.3 | 47 | 4.6 | 35% |
| Middlegame | 343 | 78.7 | 102 | 10.2 | 32% |
| Endgame | 134 | 79.0 | 84 | 4.5 | 30% |
Chess960
- Rating
- 1,08595%: 926 to 1,244
- Record
- 13 won, 1 drawn, 10 lost of 24
- Accuracy (open positions)
- 78.4
- Accuracy (all moves)
- 83.7
- Average centipawn loss
- 94
- Blunders / mistakes / inaccuracies per 100 moves
- 9.4 / 7.1 / 13.1
- Matched Stockfish's first choice
- 26%
- In Stockfish's top three
- 51%
- Legal on the first try
- 96.8%
- Illegal / invalid
- 31 of 894 answers
- Forfeits
- 0
- Adjudicated games
- 13
- API-equivalent cost per game
- $0.060
- API-equivalent cost per move
- $0.0017
- Seconds per move
- 16.2
- Model minutes per game
- 9.7
- Tokens per move (in / out)
- 1,114 / 2,889
- Reasoning tokens per move
- 2,782
- Aborted on our side (not counted)
- 1
By phase
| Phase | Moves | Accuracy | Centipawn loss | Blunders /100 | Engine match |
|---|---|---|---|---|---|
| Opening | 240 | 77.8 | 79 | 12.5 | 18% |
| Middlegame | 393 | 76.9 | 116 | 11.2 | 30% |
| Endgame | 230 | 84.3 | 72 | 3.0 | 29% |
Games
Standard as blackWon vs Skill 0, 25% random moves44 plies · adjudicated: decisive advantage · $0.025Chess960 as blackLost vs Skill 0, 25% random moves67 plies · checkmate · $0.066Standard as whiteLost vs Stockfish 150063 plies · adjudicated: decisive advantage · $0.039Chess960 as whiteLost vs Stockfish Skill 036 plies · checkmate · $0.032Standard as blackWon vs Skill 0, 10% random moves38 plies · adjudicated: decisive advantage · $0.024Chess960 as blackWon vs Skill 0, 10% random moves80 plies · adjudicated: decisive advantage · $0.067Standard as whiteWon vs Skill 0, 10% random moves49 plies · adjudicated: decisive advantage · $0.026Chess960 as whiteLost vs Skill 0, 10% random moves135 plies · adjudicated: decisive advantage · $0.128Standard as blackLost vs Stockfish 132043 plies · checkmate · $0.039Chess960 as blackLost vs Stockfish 132067 plies · checkmate · $0.067Standard as whiteWon vs Skill 0, 10% random moves91 plies · adjudicated: decisive advantage · $0.069Chess960 as whiteWon vs Skill 0, 10% random moves45 plies · adjudicated: decisive advantage · $0.034Standard as blackWon vs Skill 0, 25% random moves56 plies · adjudicated: decisive advantage · $0.044Chess960 as blackWon vs Skill 0, 25% random moves34 plies · adjudicated: decisive advantage · $0.023Standard as whiteLost vs Stockfish Skill 057 plies · adjudicated: decisive advantage · $0.038Chess960 as whiteLost vs Stockfish Skill 079 plies · adjudicated: decisive advantage · $0.059Standard as blackLost vs Skill 0, 10% random moves106 plies · adjudicated: decisive advantage · $0.069Chess960 as blackWon vs Skill 0, 10% random moves48 plies · adjudicated: decisive advantage · $0.039Standard as whiteLost vs Skill 0, 10% random moves69 plies · adjudicated: decisive advantage · $0.035Chess960 as whiteWon vs Skill 0, 10% random moves101 plies · adjudicated: decisive advantage · $0.102Standard as blackLost vs Stockfish Skill 077 plies · checkmate · $0.054Chess960 as blackLost vs Stockfish 1320105 plies · checkmate · $0.084Standard as whiteLost vs Stockfish 132063 plies · adjudicated: decisive advantage · $0.056Chess960 as whiteLost vs Skill 0, 10% random moves44 plies · checkmate · $0.032Standard as blackWon vs Skill 0, 25% random moves46 plies · adjudicated: decisive advantage · $0.030Chess960 as blackWon vs Skill 0, 25% random moves74 plies · checkmate · $0.067Standard as whiteLost vs Stockfish Skill 237 plies · adjudicated: decisive advantage · $0.021Chess960 as whiteWon vs Stockfish Skill 0105 plies · adjudicated: decisive advantage · $0.073Standard as blackLost vs Stockfish 132029 plies · checkmate · $0.016Chess960 as blackWon vs Skill 0, 10% random moves80 plies · adjudicated: decisive advantage · $0.058Standard as whiteWon vs Skill 0, 10% random moves89 plies · adjudicated: decisive advantage · $0.072Chess960 as whiteWon vs Skill 0, 25% random moves57 plies · adjudicated: decisive advantage · $0.049Standard as blackWon vs Stockfish 132052 plies · adjudicated: decisive advantage · $0.028Chess960 as blackLost vs Skill 0, 10% random moves102 plies · adjudicated: decisive advantage · $0.082Standard as whiteWon vs Skill 0, 10% random moves47 plies · adjudicated: decisive advantage · $0.027Chess960 as whiteWon vs Skill 0, 10% random moves49 plies · checkmate · $0.042Standard as blackWon vs Skill 0, 25% random moves72 plies · checkmate · $0.048Chess960 as blackWon vs Skill 0, 25% random moves50 plies · adjudicated: decisive advantage · $0.036Standard as whiteLost vs Stockfish Skill 0129 plies · adjudicated: decisive advantage · $0.101Chess960 as whiteDrew vs Skill 0, 10% random moves125 plies · threefold repetition · $0.099Standard as blackWon vs Skill 0, 10% random moves50 plies · adjudicated: decisive advantage · $0.033Chess960 as blackLost vs Skill 0, 10% random moves67 plies · checkmate · $0.060Standard as whiteLost vs Skill 0, 10% random moves66 plies · checkmate · $0.061Chess960 as whiteWon vs Skill 0, 25% random moves87 plies · adjudicated: decisive advantage · $0.076Standard as blackLost vs Stockfish 150023 plies · checkmate · $0.011Chess960 as blackWon vs Skill 0, 25% random moves54 plies · checkmate · $0.044Standard as whiteWon vs Skill 0, 25% random moves31 plies · checkmate · $0.018Chess960 as whiteLost vs Skill 0, 25% random moves30 plies · checkmate · $0.021