Anthropic Makes Claude Sonnet 5's Introductory Pricing Permanent

Anthropic has confirmed that Claude Sonnet 5’s introductory API pricing is now permanent, canceling a previously scheduled price increase that was set to take effect on September 1, 2026.

Details

• The original plan: When Claude Sonnet 5 launched in June 2026, Anthropic priced it at $2 per million input tokens and $10 per million output tokens as introductory pricing through August 31, with a scheduled increase to $3 input / $15 output tokens set to begin September 1
• What changed: Anthropic announced the $2/$10 pricing will remain in place indefinitely — the September 1 increase to $3/$15 “will not occur,” according to the updated pricing documentation
• Where it was confirmed: The change is reflected in Anthropic’s official API pricing documentation and was also announced via Anthropic’s Claude account, stating the introductory price “will remain unchanged”
• Context versus Sonnet 4.6: Sonnet 5’s now-permanent $2/$10 pricing is lower per-token than Sonnet 4.6’s $3/$15, though Sonnet 5 uses a new tokenizer that produces roughly 30% more tokens for the same text, so the effective cost of an equivalent request doesn’t drop in direct proportion to the headline per-token price cut
• Batch pricing: The batch API discount continues to apply on top of the permanent rate, putting batched Sonnet 5 usage at $1 per million input tokens and $5 per million output tokens

What happened next

The move removes a cost uncertainty that developers building on Sonnet 5 had been budgeting around since launch, and signals Anthropic is treating Sonnet 5’s price point as a competitive anchor rather than a temporary promotion. It comes about three weeks after Anthropic released Claude Opus 5, keeping the broader Claude lineup’s pricing structure stable heading into the fall.