Anthropic releases Claude Sonnet 5.5, up to 30% cheaper per task

Anthropic released Claude Sonnet 5.5 on 28 September 2026, the second model in its Claude 5.5 family. The company calls it a clear upgrade over Sonnet 5: it generates output more than 30 percent faster and needs fewer tokens for the same work, cutting the cost per task by up to 30 percent.

Sonnet 5.5 is positioned as a cheaper, faster complement to Claude Opus 5.5. Opus 5.5 targets complex work that demands careful judgment, while Sonnet 5.5 is built for well-scoped everyday tasks: fixing bugs and producing polished documents, slides and spreadsheets. Claude Haiku 5.5, aimed at high-volume, cost-sensitive applications, follows in the coming weeks.

Benchmarks close to Opus 5.5

The jump over Sonnet 5 is sharpest in coding. On Terminal-Bench 4.0, an agentic coding evaluation, Sonnet 5.5 scores 70.6 percent against Sonnet 5's 10.3 percent. On CursorBench 4.0, built from real Cursor sessions, it reaches 55.5 percent versus 34.1 percent, about two points below Opus 5.5 at 57.8 percent. On FrontierCode 1.1 it scores 52.1 percent at Xhigh effort, ten points above its predecessor at roughly one fifteenth of the cost per task.

Knowledge work and reasoning

On GDPval-AA v2.1, which covers tasks from 44 occupations and nine industries, Sonnet 5.5 records 1,844 points, nearly level with Opus 5.5 at 1,846 and about 400 points above Sonnet 5. Chartography, a visual chart-recognition test, rises from 15.6 to 61.6 percent. Anthropic cautions that benchmarks capture only one facet of a model's abilities, and that Opus 5.5 remains clearly stronger at complex, open-ended work.

Same token price, fewer tokens per task

Per-token pricing is unchanged from Sonnet 5: $2 per million input tokens, $10 per million output tokens and $0.20 per million for cache reads. The saving comes from token efficiency, not a price cut, which is why Anthropic states it as up to 30 percent per task. Output generation is also more than 30 percent faster. Early testers found the model grasps a codebase quickly and batches tool calls more often, which cuts the number of steps.

Availability and new safeguards

Claude Sonnet 5.5 is available now on Amazon Web Services, Google Cloud and Microsoft Azure with zero data retention as standard, and the model ID is claude-sonnet-5-5. Because its cybersecurity abilities are comparable to Opus 5's, it is the first Sonnet to ship with cyber safeguards: high-risk security requests visibly fall back to Sonnet 5, while routine software development is unaffected. It is also the first Sonnet with classifiers that block reasoning extraction, added to counter distillation attacks.