How much does Claude Sonnet 5 cost?

As of July 2026, Claude Sonnet 5 costs $2 per million input tokens and $10 per million output tokens — but that's introductory pricing with a hard deadline. It runs through August 31, 2026; from September 1, standard pricing of $3 per million input and $15 per million output takes effect, a 50% increase on both sides.

Two mechanisms cut the effective rate well below list price. Prompt caching makes repeated input (system prompts, large documents, codebase context) up to 90% cheaper on reads, with cache writes billed at 1.25× the base input rate — and on the Claude API, cached reads don't count against your rate limits at all. The Batch API takes 50% off both input and output for work that can run asynchronously.

For context against rivals at the same price point: OpenAI's GPT-5.6 Terra runs $2.50/$15 and Google's Gemini 3.1 Pro runs $2/$12 (rising to $4/$18 above 200K input tokens, where Sonnet 5 bills flat across its full 1M window). The practical takeaway: if you're evaluating Sonnet 5, doing it before the August 31 deadline means your testing happens at the discounted rate — and your budget math should use the $3/$15 standard price for anything long-term.