Artificial intelligence · September 2026

Claude Opus 5.5

Frontier agentic coding gets about 40% cheaper.

Claude Opus 5.5 is priced at $4 and $20 per million tokens, about 40% less than Opus 5 on typical work. One early tester finished a 680,000-line code migration in under a day.

See it in the living tree Wikipedia Source

Arcs above join it to what it stood on, arcs below to what it led to. The bar places this stretch on the tree's whole timeline.

What it built on 1

Claude Opus 5 2026

Watch

Introducing Claude Opus 5.5Claude · YouTube

Related measurements

The dashed line marks when it first worked.

Best AI score on GPQA Diamond Latest: 95.8 % correct (2026) Source: Epoch AI, Capabilities & benchmarking (benchmark_data.zip, gpqa_diamond.csv); Anthropic: Claude 3 public launch (March 4, 2024)

Training compute of notable AI models Source: Epoch AI, Notable AI Models (CC BY 4.0)