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Claude Fable 5.1 API pricing
Claude Fable 5.1 is a flagship model from Anthropic with a 1,000,000-token context window. Rates below are per 1,000,000 tokens, verified October 2026.
Price list
| Token class | Rate / 1M | Notes |
|---|---|---|
| Input | $10 | Prompt tokens not served from cache |
| Cached input | $0.25 | 98% below base input |
| Cache write | $12.50 | Charged once when the prefix is stored |
| Output | $50 | 5.0× the input rate |
| Batch API | −50% | Input and output, results within 24 h |
Released Sep 1, 2026. Cache read cut 75% ($1.00 → $0.25).
What Claude Fable 5.1 costs at three real workloads
Sticker prices rarely match the invoice. These three workloads use the rates above, with cache writes charged once per job and the batch discount applied only where the provider offers it.
| Workload | Requests | Tokens | Estimated cost |
|---|---|---|---|
| Support chat | 1,000 | 4K in / 600 out | $70 |
| RAG with caching | 1,000 | 50K in (45K cached) / 1K out | $112 |
| Nightly batch job | 10,000 | 10K in / 2K out | $1000 |
Caching the 45K-token prefix saves about 80% on the RAG workload versus sending it uncached every call ($550 → $112). Batch mode halves the nightly job.
Where Claude Fable 5.1 sits in the market
Out of 28 models in this dataset, Claude Fable 5.1 ranks #28 cheapest by input rate, #28 by output rate, and #28 on a blended 1M-input-plus-250K-output workload.
| Model | Provider | Input | Output | Blended |
|---|---|---|---|---|
| Claude Fable 5.1 | Anthropic | $10 | $50 | $22.50 |
| GPT-6 Astra | OpenAI | $10 | $50 | $22.50 |
| GPT-5.5 | OpenAI | $5 | $30 | $12.50 |
| Claude Opus 5 | Anthropic | $5 | $25 | $11.25 |
Blended cost = 1M input tokens + 250K output tokens at list price.
FAQ
How much does Claude Fable 5.1 cost per 1M tokens?
$10 per 1M input tokens and $50 per 1M output tokens on the standard tier.
Is prompt caching cheaper on Claude Fable 5.1?
Yes. Cached input bills at $0.25 per 1M tokens, 97.5% below the $10 base input rate, with a one-off cache write at $12.50 per 1M.
Does Claude Fable 5.1 support the Batch API?
Yes. Batch requests bill at roughly half the standard input and output rates: the nightly job above costs $2000 at list price and about $1000 in batch mode.