Anthropic cancels Claude Sonnet 5's scheduled price increase, keeping $2/$10 permanent

Anthropic will not raise Claude Sonnet 5's API pricing on September 1 as originally planned, according to a note on the official Claude Platform pricing page. The $2 per million input token / $10 per million output token rate introduced at launch is now the model's standard, permanent price.

What's new

Anthropic's pricing documentation now states directly: "The $2/$10 per million input/output token pricing for Claude Sonnet 5, announced at launch as introductory pricing through August 31, 2026, is now the standard price. The previously scheduled increase to $3/$15 per million input/output tokens on September 1, 2026 will not occur."

That reverses a change developers had been bracing for. Sonnet 5 launched with $2/$10 pricing explicitly labeled as a limited-time introductory rate, set to expire August 31 and revert to $3 input / $15 output — a 50% jump on both input and output tokens. Anthropic's Claude Sonnet 5 announcement page separately confirms the reversal, noting the introductory pricing "is now permanent" and that the September 1 increase "no longer applies."

The pricing page also reiterates a related cost factor that remains unchanged: Sonnet 5 uses a newer tokenizer, shared with Claude 4.7-and-later models, that "produces approximately 30% more tokens for the same text" compared with the previous tokenizer used by Sonnet 4.6 and earlier. Per-token price holds steady, but the same request can still cost more in practice because it now maps to more tokens — Anthropic puts the range at roughly 1.0 to 1.35x depending on content type.

Context

Sonnet 5's $2/$10 rate already undercut the $3/$15 pricing of its predecessor, Claude Sonnet 4.6, which remains available at the higher rate. Had the scheduled increase gone through, Sonnet 5 would have matched Sonnet 4.6 and Sonnet 4.5's $3/$15 pricing exactly, erasing the headline discount that accompanied its launch. Batch API pricing for Sonnet 5 ($1 input / $5 output, a 50% discount off the standard rate) is unaffected and continues to undercut Sonnet 4.6's batch rate of $1.50/$7.50.

Anthropic has not published a separate announcement explaining the reversal; the confirmation lives in an update to the standing pricing documentation itself, reflected in both the general pricing page and the original Sonnet 5 launch page.

Why it matters

For any team that budgeted around a September 1 cost increase, this removes a planned 50% jump in per-token pricing for Sonnet 5 workloads — Anthropic's mainstream production model, positioned between Haiku for simple tasks and Opus for the hardest reasoning work. Locking in introductory pricing as permanent also puts continued pressure on the field: Sonnet 5 stays priced below Sonnet 4.6, and undercuts what many competing frontier-tier models charge for comparable input tokens. The tokenizer change is the detail worth double-checking on any cost model that assumes stable token counts: a workload can still see its effective bill rise even with per-token pricing unchanged, simply because the same text now tokenizes into more tokens.