Claude Sonnet 5 Is Here: Opus-Level Performance
- Sonnet 5 delivers near Opus 4.8-level performance at Sonnet pricing.
- Introductory pricing is $2/$10 per million tokens until Aug. 31. Standard pricing: $3/M input, $15/M output.
- Hidden change: Sonnet 5 uses the Opus 4.7 tokenizer, so the same prompt may use up to ~35% more tokens, increasing effective costs.
- Reasoning, coding, tool use, and agentic capabilities have all seen major improvements.
It's now the default model for Free and Pro users, and is available in Claude, Claude Code, and the API.