Claude Sonnet 5.5: Pricing, Efficiency and How It Compares With Opus 5.5

Anthropic released Claude Sonnet 5.5 on September 28, 2026, as the second model in its Claude 5.5 family, after Opus 5.5. Its headline change is efficiency rather than a lower API rate: Sonnet 5.5 keeps Sonnet 5’s per-token prices, while Anthropic says it generates outputs more than 30% faster and can cost up to 30% less per task.

Sonnet 5.5 pricing and claimed efficiency

Sonnet 5.5 costs $2 per million input tokens and $10 per million output tokens—the same listed rates as Sonnet 5. Anthropic attributes the potential task-level savings to completing work with fewer tokens; reporting on the launch also describes fewer tool calls.

That distinction matters when estimating API spend: the price of each token is unchanged, but a task that uses fewer tokens may cost less overall. The “up to 30%” figure is Anthropic’s reported result, not a guaranteed reduction for every prompt, workflow or production workload.

Sonnet 5.5 vs. Sonnet 5 and Opus 5.5

Model	Input / output price per million tokens	Intended role
Claude Sonnet 5	$2 / $10	Sonnet 5.5’s predecessor; its listed rates are unchanged in the new release.
Claude Sonnet 5.5	$2 / $10	Faster, lower-cost-per-task option for well-scoped everyday work, including coding and creating documents, slides and spreadsheets.
Claude Opus 5.5	$4 / $20	Higher-priced option positioned for complex work that requires careful judgment.

Opus 5.5’s listed input and output rates are twice Sonnet 5.5’s. Anthropic presents the models as complements: Sonnet for more routine, clearly scoped tasks and Opus for work where greater capability and careful judgment are the priority.

Enterprise availability and what comes next

Anthropic’s release notes list Sonnet 5.5 on the Claude API and through offerings on Amazon, Google Cloud and Microsoft’s platform. The company also says Haiku 5.5, aimed at high-volume and cost-sensitive applications, is expected to join the family in the coming weeks; the cited announcement does not give a specific release date or price.

The launch expands Anthropic’s model lineup ahead of a reported planned IPO. It also follows CEO Dario Amodei’s call for the AI community to slow the pace of releasing new capabilities over safety concerns. Those developments provide context for the release, but do not by themselves establish how Sonnet 5.5 changes the company’s safety approach. 1