Anthropic releases Claude Sonnet 5.5, its faster everyday frontier model
Anthropic says Sonnet 5.5 runs more than 30% faster than Sonnet 5 and uses fewer tokens per completed task at the same list price.
Anthropic released Claude Sonnet 5.5 on 28 September 2026 as the faster, lower-cost counterpart to Claude Opus 5.5. It is available in Claude, Claude Code and the Claude API, as well as through Amazon Bedrock, Google Cloud and Microsoft Foundry.
List pricing remains $2 per million input tokens and $10 per million output tokens, with cache reads at $0.20 per million. Anthropic says the model generates output more than 30% faster than Sonnet 5 and costs up to 30% less per completed task because it generally uses fewer tokens. Those comparisons are vendor-reported.
Anthropic reports 70.6% on Terminal-Bench 4.0 and 46.2% on the main FrontierCode 1.1 set at maximum effort. Artificial Analysis independently scores the highest-effort configuration at 56 on Intelligence Index v4.3.2, second only to Claude Opus 5.5 in the current snapshot.
Like the other Claude frontier models, Sonnet 5.5 is a hosted service without downloadable weights. It is relevant to the cost of choosing cloud inference, not to the list of models a PC can run locally.
Sources
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