Image: Anthropic / anthropic.com Anthropic Won't Raise Sonnet 5 Prices on September 1 — the Launch Rate Is Now Permanent
Anthropic made the Claude Sonnet 5 introductory price permanent on August 10. The planned September 1 increase to $3/$15 per MTok was cancelled. Input stays at $2, output at $10.
When Anthropic launched Claude Sonnet 5 in early July, the company framed the $2 input / $10 output price as introductory, with a scheduled increase to $3 input / $15 output per million tokens on September 1, 2026. That increase is not happening. On August 10, Anthropic updated its pricing documentation to make the launch rate permanent. The platform docs now say plainly that the September 1 change will not occur.
The pricing page at platform.claude.com reflects this: $2 per million input tokens, $10 per million output tokens, with no scheduled change. Cache writes are $2.50 per million tokens and cache reads $0.20.
Why this matters now
September 1 is four days away. Teams that had modeled a 50% API cost increase into their Q4 budgets can remove that line item. If you adjusted application logic, switched model tiers, or made any other changes in anticipation of the price increase, those decisions are worth revisiting against the now-permanent rate.
The context window on Sonnet 5 is 200,000 tokens. The model is available through the Anthropic API, Claude.ai, and Amazon Bedrock, and it supports prompt caching, batch processing, and tool use at the same rate structure.
What about the other models?
The price freeze applies specifically to Sonnet 5. The rest of the Claude pricing remains unchanged: Opus 5 at $15 input / $75 output, Haiku 4.5 at $0.80 input / $4 output. Fable 5 is separately priced and not affected by this change.
If you’re running a mix of models across a production deployment, the cost-optimize command added in Claude Code 2.1.247 can now profile your API spend against these current rates and suggest where caching, batching, or model selection adjustments would reduce cost.
What drove the reversal?
Anthropic hasn’t explained the decision publicly beyond updating the pricing documentation. A likely factor is competition: Google’s Gemini 3.7 Flash, priced at half of its predecessor, and other frontier providers have kept pressure on the mid-tier coding model segment. Locking in the $2/$10 rate removes pricing uncertainty as a reason for teams to evaluate alternatives.
For developers who were already running Sonnet 5 at the current rate, nothing changes. For teams that held off on adopting Sonnet 5 because of the planned September 1 increase, that barrier is gone.