AI models · Updated 2026-10-31

Claude Opus 5.5: where it fits

What changed from Opus 5, who benefits from Opus 5.5, and what a typical API month costs.

What changed

Opus 5.5 replaces Opus 5 as Anthropic’s current Opus release. Anthropic reports stronger agentic coding and knowledge-work results, output generation over 30% faster, and 40% lower cost on typical workloads than Opus 5. Per-token rates also fell: input moved from $5 to $4 per million and output from $25 to $20; cache reads moved from $0.50 to $0.20. Both releases have a 1 million token context window.

The vendor’s benchmark comparisons use different effort settings and task harnesses, so they do not establish that Opus 5.5 will win on every codebase or writing task. Run your own repeated tasks before changing a whole suite.

Who should switch

Try Opus 5.5 when Opus 5 is already your choice for multi-file coding, long-running agents, research, or professional documents. It is a reasonable daily driver when you want one strong general model: Anthropic’s current model guidance recommends starting with Opus 5.5 for most workloads.

Who should stay put

Keep Opus 5 where a pinned integration, tool behavior, or established evaluation still favors it. The migration guide and task-specific checks matter more than a leaderboard when you depend on exact tool calls or outputs.

Cost for a typical API month

Assume 2 million input tokens and 500,000 output tokens, before cache, tools, or other charges. Opus 5.5 costs about $18 at list rates: $8 input plus $10 output. The same volume at Opus 5 list rates is about $22.50. Anthropic reports a larger 40% average reduction on its typical workload mix because Opus 5.5 also uses fewer tokens per task. A Claude Pro subscription is $20/month and includes Opus access, with usage limits; that subscription does not pay for API calls.

Place in a suite

Use Opus 5.5 as a daily driver for demanding work. Route routine, well-specified work to Sonnet 5.5 and repeated classification or summarization to Haiku 5.5 after checking the quality tradeoff on your own examples.