MadeByLupu@bylupu
Results updated 2026-10-26 UTC

Claude Sonnet 5.5 chess results⁠

Compare Claude Sonnet 5.5's saved thinking setups, ChessBench ratings, time, cost, and match records.

ChessBench Elo ratings compare LLMs within this benchmark only. They are not equivalent to Chess.com, FIDE, or other chess ratings. Beating a 2000-rated LLM here does not establish your rating or predict the same result against a 2000-rated human player.

xHigh #3

2089 ChessBench Elo

Placement complete · 74 rated games

Wins / draws / losses
65 / 0 / 9
Result percentages
88% / 0% / 12%
Time per turn
37.5s
Cost per game
$2.228
Output tokens per game
146,849
Rejected %
1.00%

Medium #12

1641 ChessBench Elo

Placement complete · 74 rated games

Wins / draws / losses
36 / 8 / 30
Result percentages
49% / 10% / 41%
Time per turn
9.7s
Cost per game
$0.455
Output tokens per game
14,546
Rejected %
1.28%

How to read this comparison

Each thinking setup has its own rating and completed-game record. Higher thinking settings do not guarantee more wins. The figures above use the same saved data as the leaderboard.

Time includes model requests per accepted move. Cost uses fully priced completed benchmark games. Output includes reported reasoning tokens. Human challenges are separate.

Public match records

Page 2 of 8. 146 visible replays. Rating totals include all retained rated results; an archive-hidden result has no link here.

  1. DeepSeek V4.1 Flash (1017) (High) vs Claude Sonnet 5.5 (Medium)1-0

    Checkmate · 147 half-moves · 2026-10-17 UTC

  2. DeepSeek V4.1 Flash (1017) (High) vs Claude Sonnet 5.5 (xHigh)0-1

    Checkmate · 84 half-moves · 2026-10-17 UTC

  3. Claude Sonnet 5.5 (Medium) vs DeepSeek V4.1 Flash (1017) (High)1-0

    Checkmate · 119 half-moves · 2026-10-17 UTC

  4. Claude Sonnet 5.5 (xHigh) vs DeepSeek V4.1 Flash (1017) (High)1-0

    Checkmate · 81 half-moves · 2026-10-17 UTC

  5. Gemini 4 Argon (High) vs Claude Sonnet 5.5 (Medium)1-0

    Checkmate · 47 half-moves · 2026-10-13 UTC

  6. Claude Sonnet 5.5 (xHigh) vs Gemini 4 Argon (High)1-0

    Checkmate · 95 half-moves · 2026-10-13 UTC

  7. Claude Sonnet 5.5 (Medium) vs Gemini 4 Argon (High)0-1

    Checkmate · 60 half-moves · 2026-10-13 UTC

  8. Gemini 4 Argon (High) vs Claude Sonnet 5.5 (xHigh)1-0

    Checkmate · 41 half-moves · 2026-10-13 UTC

  9. Claude Sonnet 5.5 (xHigh) vs Gemini 4 Argon (Medium)1-0

    Checkmate · 111 half-moves · 2026-10-13 UTC

  10. Gemini 4 Argon (Medium) vs Claude Sonnet 5.5 (Medium)1-0

    Checkmate · 59 half-moves · 2026-10-13 UTC

  11. Gemini 4 Argon (Medium) vs Claude Sonnet 5.5 (xHigh)0-1

    Checkmate · 110 half-moves · 2026-10-13 UTC

  12. Claude Sonnet 5.5 (Medium) vs Gemini 4 Argon (Medium)0-1

    Checkmate · 62 half-moves · 2026-10-13 UTC

  13. Claude Haiku 5.5 (xHigh) vs Claude Sonnet 5.5 (xHigh)0-1

    Checkmate · 90 half-moves · 2026-10-07 UTC

  14. Claude Sonnet 5.5 (Medium) vs Claude Haiku 5.5 (xHigh)0-1

    Checkmate · 102 half-moves · 2026-10-07 UTC

  15. Claude Sonnet 5.5 (xHigh) vs Claude Haiku 5.5 (xHigh)1-0

    Checkmate · 81 half-moves · 2026-10-07 UTC

  16. Claude Haiku 5.5 (xHigh) vs Claude Sonnet 5.5 (Medium)1/2-1/2

    Draw at 150 total moves · 150 half-moves · 2026-10-07 UTC

  17. Claude Sonnet 5.5 (xHigh) vs Claude Haiku 5.5 (Medium)1-0

    Checkmate · 99 half-moves · 2026-10-07 UTC

  18. Claude Haiku 5.5 (Medium) vs Claude Sonnet 5.5 (Medium)1/2-1/2

    Insufficient material · 99 half-moves · 2026-10-07 UTC

  19. Claude Haiku 5.5 (Medium) vs Claude Sonnet 5.5 (xHigh)0-1

    Checkmate · 72 half-moves · 2026-10-07 UTC

  20. Claude Sonnet 5.5 (Medium) vs Claude Haiku 5.5 (Medium)1-0

    Checkmate · 87 half-moves · 2026-10-07 UTC

Cite these results

ChessBench. Claude Sonnet 5.5 chess results. https://chessbench.org/models/claude-sonnet-5.5. Retrieved 2026-10-28. Include the model, thinking level, protocol, and sample size when citing results.

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