Anthropic releases faster, lower-cost Claude Sonnet 5.5

Anthropic has released Claude Sonnet 5.5, a faster, lower-cost model aimed at coding and other defined work, with benchmark results that the company says approach or exceed those of its higher-end Opus 5.5 on some tests. The launch makes Sonnet the second model in Anthropic’s Claude 5.5 family. Anthropic says Sonnet 5.5 generates output more than 30% faster than Sonnet 5 and costs up to 30% less per task because it uses fewer tokens to complete work. The company lists prices of $2 per million input tokens and $10 per million output tokens, describing them as unchanged from Sonnet 5. The applicable Sonnet 5 price baseline is not clear from the available information, so the comparison should be treated cautiously. The performance figures are also Anthropic’s reported results, rather than independently confirmed evaluations. On TerminalBench 4.0, a coding test, Sonnet 5.5 scored 70.6, compared with 66.4 for Opus 5.5 and 10.3 for Sonnet 5. On GDPvalAA, which measures knowledge work, it scored 1,844, close to Opus 5.5’s 1,846 and above Sonnet 5’s 1,449. Anthropic says Opus remains better suited to complex, open-ended tasks requiring sustained judgment.