Compare models
Put models side by side on price, context, capabilities, and benchmarks.
Claude Opus 5.5 is Anthropic's flagship model released September 22, 2026 as the first of the Claude 5.5 family, with a 1M-token context window, text, image, and file input, and pricing of $4/$20 per million input/output tokens. Anthropic says it performs at the level of Claude Fable 5.1 on most work while costing about 40% less to run than Opus 5, and it leads on agentic coding, multi-step changes in large codebases, and long-horizon knowledge work.
Claude Sonnet 5.5 is Anthropic's Sonnet-class model (1M-token context, 128K max output, $2/$10 per million input/output tokens), released September 28, 2026 as a direct upgrade to Sonnet 5 and a faster, lower-cost complement to Opus 5.5. It generates output over 30% faster with fewer tokens per task, and is strongest at well-scoped everyday work such as building features, fixing bugs, and producing polished documents, slides, and spreadsheets.
Benchmarks
Head-to-head scores across reasoning, coding, and agentic indices, plus per-domain rankings.