Claude Sonnet 5.5 Ships 30 Percent Faster and Cheaper
Anthropic released Claude Sonnet 5.5 on September 28 US time, the second model in the Claude 5.5 family after Opus 5.5 arrived on September 22. Output generation is more than 30 percent faster than Claude Sonnet 5 and cost per task is up to 30 percent lower, with API pricing unchanged at 2 dollars per million input tokens and 10 dollars per million output tokens. On Terminal-Bench 4.0, which measures command-line work, the score rose from 10.3 percent for Sonnet 5 to 70.6 percent. OSWorld 2.1 reached 80.1 percent and Chartography 61.6 percent. On Anthropic's GDPval-AA v2.1 table, Sonnet 5.5 scored 1844, two points behind Opus 5.5 at 1846 and roughly 400 above Sonnet 5. Against OpenAI's GPT-6 Sol, which shares the same API unit price, the knowledge-work gap is large: 1844 to 1487 on GDPval-AA v2.1 and 1811 to 1483 on AA-Briefcase v1.1. The model is available across Claude apps, the API, Amazon Web Services, Google Cloud, and Microsoft Azure. Claude Haiku 5.5 is planned within weeks.