Anthropic Launches Claude Sonnet 5.5 With Faster Output and Lower Per-Task Costs

Anthropic has released Claude Sonnet 5.5, which it says generates output more than 30% faster than Sonnet 5 and costs up to 30% less per task. The new model is aimed at everyday coding and document work, while Opus 5.5 remains stronger for complex, open-ended tasks.

In the company's published results, Sonnet 5.5 scored 70.6% on Terminal-Bench 4.0, an agentic coding test, compared with 10.3% for Sonnet 5. On GDPval-AA, which evaluates work across 44 occupations, it scored 1844, nearly matching Opus 5.5's 1846. That GDPval result came from a pre-release build with a bug that could have reduced the score.

Early testers reported that the model understood codebases faster and completed tasks in fewer steps by batching tool calls. It is also the first Sonnet model to finish Pokémon Red using only screenshots.

API token prices have not changed: Sonnet 5.5 costs $2 per million input tokens, $10 per million output tokens, and $0.20 per million cache-read tokens. In company testing, the model used fewer tokens to complete the same work, lowering the cost per task. Effort defaults to Medium in Claude Code and the Claude apps, and High on the Claude Platform.

The model is available now through Anthropic and cloud partners, including Amazon Web Services, Google Cloud, and Microsoft Azure, under the identifier claude-sonnet-5-5. A zero-data-retention option is available. Because its cybersecurity capabilities are comparable to Opus 5's, some higher-risk requests will fall back to Sonnet 5; routine software development remains available.

Sonnet 5.5 follows last week's Opus 5.5 release and replaces Sonnet 5. Haiku 5.5 is expected in the coming weeks.