Claude Sonnet 5.5
2026-09-28 · Publisher : Anthropic · Domain : Artificial Intelligence
Anthropic launches Claude Sonnet 5.5, the second model of the 5.5 family: more than 30% faster than Sonnet 5 and up to 30% cheaper for most tasks, at the same price per token.
What changes
- Clear upgrade over Sonnet 5: fewer tokens per task, faster generation.
- Complement to Opus 5.5: the most efficient on well-scoped tasks, bug fixes and polished documents, presentations and spreadsheets.
- First Sonnet to complete Pokémon Red from screenshots.
- Cyber safeguards comparable to those of Opus 5.5.
### Specifications - Context window: 1 M tokens. Maximum output: 128,000 tokens. Adaptive thinking. - Knowledge cutoff: June 2026 (models page). - Availability: all platforms (AWS, Google Cloud, Azure). API identifier: `claude-sonnet-5-5`. ### Pricing | Item | Price (USD per million tokens) | | --- | --- | | Input | 2 | | Output | 10 | | Cache write 5 min / 1 h | 2.50 / 4 | | Cache read | 0.20 | | Batch (input / output) | 1 / 5 | ### Benchmarks Scores published by the vendor. | Evaluation | Sonnet 5.5 | Sonnet 5 | Opus 5.5 | | --- | --- | --- | --- | | Terminal-Bench 4.0 | 70.6% | 10.3% | 66.4% | | FrontierCode 1.1 | 46.2% | 42.4% | 54.4% | | CursorBench 4.0 | 55.5% | 34.1% | 57.8% | | GDPval-AA v2.1 | 1844 | 1449 | 1846 | | Humanity's Last Exam (with tools) | 64.5% | 54.9% | 67.7% | | OSWorld 2.1 (partial) | 80.1% | 57.0% | 81.8% | | Chartography (without tools) | 61.6% | 15.6% | 64.4% | ### Key takeaways Sonnet 5.5 catches up with Opus 5.5 on several evaluations for half the price, making it the economical choice for everyday tasks.
Links
Tags : LLM, Anthropic, Claude, Sonnet, Claude 5.5, Agents