Claude Haiku 5.5: release report
Anthropic released Claude Haiku 5.5 on October 7, 2026. Specs, price, where it ranks, how it plays chess and how it solves sudoku.
The release
Anthropic released Claude Haiku 5.5 on October 7, 2026. Read the announcement.
Fast Claude model for responsive assistance, classification, and lightweight agents.
- Context window: 1,000,000 tokens, up to 128,000 out
- Takes text, image and PDF. Returns text.
- Reasoning model.
- Closed weights.
Anthropic's release before this was Claude Sonnet 5.5 on September 28, 2026, 9 days earlier. Over the past year it has shipped a model every 22.5 days on median (13 releases).
Price
$0.10 per million input tokens and $0.50 per million output tokens on Anthropic's API. Cached input is $0.010. Claude Haiku 4.5, the model it follows, costs $1.00 and $5.00.
Where it ranks
Added October 15, 2026.
Epoch AI's Capabilities Index puts it at 159.0 (95% interval 156.6 to 162.1), number 14 of 277 models Epoch has scored. The frontier reached this level 7.1 months before it shipped.
Our chess benchmark
Added October 15, 2026.
Rated 1,102 (95% interval 903 to 1,301) over 16 games against calibrated Stockfish, number 6 of 9 models we've tested. Standard chess 1,242, Chess960 985.
In standard chess: 86.0 accuracy in open positions, 4.7 blunders per 100 moves, 2.4% of answers were illegal moves.
Each game took 8.0 minutes of model time. At the lab's list price its tokens would cost $0.049 a game.
Our sudoku benchmark
Added October 15, 2026.
Scored 31 out of 100 (95% interval 19 to 43), number 4 of 4 models we've tested. It solved 13 of 42 grids and filled 93.1% of blank cells correctly.
By tier, from singles to grids no human technique finishes: Cozy 3 of 6, Gentle 1 of 6, Steady 1 of 6, Tricky 3 of 6, Devious 2 of 6, Expert 2 of 6, Beyond 1 of 6.
It said it was 96% sure on average; 29 wrong answers came with 90% confidence or more; 8 finished grids repeated a digit.
Each grid took 111 seconds and 30,157 output tokens on average. At the lab's list price its tokens would cost $0.015 a grid.
Each section was written on the date shown and is not revised afterwards. Specifications from Models.dev, prices from provider listings, capability scores from Epoch AI under CC BY 4.0, chess and sudoku results from Model Cadence Bench.