Claude Fable 5.1 — API Pricing & Benchmarks
Claude Fable 5.1 is Anthropic's flagship reasoning model, released in 2026-09. The API costs $10.0 per 1M input tokens and $50.0 per 1M output tokens ($20.0 blended at a 3:1 ratio), with cached input at $0.25. It supports a 1M-token context window. On the independently measured Artificial Analysis Intelligence Index it scores 65.7, ranking #1 of 68 models tracked on this site, with a median output speed of 71 tokens/sec.
Explore provider routes and additional benchmark sources for Claude Fable 5.1
| Provider | Anthropic |
| Input price / 1M tokens | $10.0 |
| Output price / 1M tokens | $50.0 |
| Cached input / 1M tokens | $0.25 |
| Blended price (3:1) | $20.0 |
| Context window | 1M |
| Max output tokens | 128K |
| Knowledge cutoff | 2026-06 |
| License | proprietary |
| Input modalities | T+I |
| Output speed (tok/s) | 71 |
| Released | 2026-09 |
| Artificial Analysis Intelligence Index | 65.7 |
| GPQA Diamond | 93.7% |
| Humanity's Last Exam | 59.1% |
Where Claude Fable 5.1 fits
On a blended 3:1 basis Claude Fable 5.1 costs $20.0 per 1M tokens, cheaper than 3% of the 80 priced models in this index. As Anthropic's flagship it is aimed at the hardest workloads — complex reasoning, agentic coding and multi-step tool use — where output quality dominates cost. Measured output speed of 71 tokens/sec is below the index median of 104 — typical of reasoning-heavy models, and worth checking against interactive latency budgets. Cached input is priced at $0.25 (98% below standard input), which rewards prompt structures with long stable prefixes — see our caching guide.
Price history
| Period | Input $/1M | Output $/1M | Cached $/1M |
|---|---|---|---|
| 2026-09-01 → current | $10.0 | $50.0 | $0.25 |
No list-price changes recorded since tracking began. Full dataset: price-history.json (CC BY 4.0).
Alternatives at a similar price
- GPT-6 Astra (OpenAI) — $20.0/1M blended, AA Index 61.2
- Claude Fable 5 (Anthropic) — $20.0/1M blended, AA Index 62.1
- GPT-5.5 (OpenAI) — $11.3/1M blended, AA Index 56.3
- Claude Opus 5 (Anthropic) — $10.0/1M blended, AA Index 63.1
Compare Claude Fable 5.1
About Anthropic
Anthropic builds the Claude family, organized into Opus (flagship), Sonnet (mid-tier) and Haiku (small) tiers alongside the Fable line. Claude models currently lead the Artificial Analysis Intelligence Index and are particularly strong on agentic-coding benchmarks such as SWE-bench Verified.