According to CoinMeta, Anthropic released Claude Sonnet 5.5 on September 28, 2026. Its performance is close to that of Opus 5.5, but it uses a larger number of tokens. The running speed of this model is over 30% faster than that of Sonnet 5, and the cost per task has been reduced by 30%. Independent benchmark testing companies reached different conclusions regarding costs after pushing the models to their limits. The price of Sonnet 5.5 is the same as that of Sonnet 5, remaining at $2 per million input tokens and $10 per million output tokens. This model scored 70.6% in the Terminal-bench 4.0 tests, while Sonnet 5 only scored 10.3%.