TL;DR — As of our last verification (2026-08-26), Claude Sonnet 5 bills $2.00 input / $10.00 output per million tokens — but that is a promotional rate Anthropic announced through August 31, 2026. At the promo price Sonnet 5 undercuts GPT-5.4 ($2.50/$15) on both sides and sits exactly 2× Haiku 4.5 and 2.5× below Opus 5. Anything you read about Sonnet 5 pricing without an as-of date is unreliable this week; the post-promo rate will be logged in our weekly-verified pricing tracker the first Friday after it changes.
The rate card (per 1M tokens, USD, verified 2026-08-26)
| Model | Input | Output | Note | |-------|-------|--------|------| | Claude Sonnet 5 | $2.00 | $10.00 | Promotional through Aug 31, 2026 | | Claude Opus 5 | $5.00 | $25.00 | Frontier workhorse | | Claude Haiku 4.5 | $1.00 | $5.00 | Value tier | | GPT-5.4 | $2.50 | $15.00 | Closest OpenAI tier | | Gemini 3 Pro | $1.25 | $5.00 | Value-frontier competitor |
Anthropic's discounts stack on top: ~90% off cached input on stable prompt prefixes and −50% via the batch API. A cached, batched Sonnet 5 call can land near Haiku-class effective pricing — which is why cache discipline matters more than the sticker price for agent workloads.
What a real month costs
At a standard workload of 10M input + 2M output tokens/month (promo rate):
- Sonnet 5: $40.00
- Haiku 4.5: $20.00 · GPT-5.4: $55.00 · Gemini 3 Pro: $22.50 · Opus 5: $100.00
Run your own input/output mix through the LLM cost calculator — output share moves the answer more than most teams expect.
Where Sonnet 5 fits in a routing ladder
- Default reasoning tier for everyday synthesis, structured writing, multi-constraint answers — the rung between Haiku (bulk) and Opus (escalation)
- Head-to-heads: vs GPT-5.4 (Sonnet wins price outright during promo) · vs Gemini 3 Pro (Gemini holds the price edge; quality on your evals decides) · vs Haiku 4.5 (the clean 2× step) · vs Opus 5 (the escalation pair)
- The promo expiry is a routing event: if the rate reverts on Sept 1, the Sonnet-vs-GPT-5.4 and Sonnet-vs-Gemini math flips for some workloads. A router that reads live pricing rebalances automatically; a hard-coded model choice does not.
Routing decision card
- Route here when: the task needs real reasoning but not frontier-grade stakes — the bulk of "thinking" traffic in most agent stacks
- Escalate up (Opus 5) when: correctness is the budget — code that ships, multi-step agent chains, analysis someone acts on
- Route down (Haiku 4.5) when: classification, extraction, short chat turns, latency-sensitive calls
- Watch: Sept 1, 2026 — re-check the tracker before trusting any Sonnet 5 comparison published in August
ClawRouters keeps Sonnet 5 in its routing pool and applies the current rate per request, so the promo — and whatever follows it — is priced in automatically. All 24 Anthropic/OpenAI/Google/DeepSeek/GLM/Kimi pairs are indexed in the model comparison index.
Pricing sourced from Anthropic's official rate card as of 2026-08-26. Promotional terms are Anthropic's; verify the live rate at anthropic.com/pricing before committing volume.