What's happening
Anthropic's published pricing lists Claude Sonnet 5 at $2 per million input / $10 per million output tokens as introductory pricing through August 31, 2026. From September 1, 2026, standard pricing takes effect: $3 / $15 per MTok — a 50% increase on both sides. (Source: Anthropic's pricing page, verified 2026-08-06.)
What it does to a real workload
A workload of 50M input + 10M output tokens/month on Sonnet 5:
| Through Aug 31 | From Sept 1 | |
|---|---|---|
| Input | $100 | $150 |
| Output | $100 | $150 |
| Monthly | $200 | $300 |
Your options
- Stay and budget it. $3/$15 matches Sonnet 4.6/4.5 pricing — the intro rate was the anomaly.
- Batch what can wait. The Batch API halves both sides ($1.50/$7.50 post-increase).
- Cache what repeats. Cache reads run 0.1× input; long shared prefixes blunt most of the increase.
- Right-size per task. Haiku 4.5 at $1/$5 handles plenty of production traffic; compare on the calculator.
Remember the tokenizer footnote: Sonnet 5 tokenizes ~30% heavier than pre-4.7 Claude models, so cross-family comparisons need real-payload benchmarks, not just rate cards.