anthropic/claude-sonnet-5.5Claude Sonnet 5.5 is Anthropic’s proprietary AI model, released Sep 28, 2026. It costs $2/M input and $10/M output tokens, and handles a 1M-token context window. Its strongest use case is agentic & tools, where it ranks in the 100th percentile of the models Model Beat tracks.
Claude Sonnet 5.5 is Anthropic's Sonnet-class model for well-scoped everyday work, succeeding Claude Sonnet 5 as a direct upgrade.
Scores on standardized evaluations. Higher is better — and rank shows where Claude Sonnet 5.5 lands among all models tracked on Model Beat.
Graduate-level scientific reasoning
Factual accuracy & hallucination
Human-rated web development
Olympiad-qualifier math
Multi-step agentic tasks
Claude Sonnet 5.5 is Anthropic's Sonnet-class model for well-scoped everyday work, succeeding Claude Sonnet 5 as a direct upgrade.
Claude Sonnet 5.5 is an AI model developed by Anthropic, part of the Claude family, released Sep 28, 2026.
Claude Sonnet 5.5's list price from Anthropic is $2 per million input tokens and $10 per million output tokens.
Claude Sonnet 5.5 supports a context window of up to 1M tokens.
On standardized evaluations tracked by Epoch AI, Claude Sonnet 5.5 scores 75.5% on APEX, 95.6% on GPQA Diamond, 1699 on WebDev Arena.
Claude Sonnet 5.5 is a proprietary model (API access), available through its provider's API rather than as a downloadable open-weight model.
Benchmark data from Epoch AI (CC BY) and Artificial Analysis; pricing, specs & descriptions from OpenRouter. Data updated Oct 1, 2026.