High-volume, cost-sensitive work
Either one
Both cost $20.00 per million tokens on a typical mix of three input tokens for every output token.
Claude Fable 5 vs Claude Fable 5.1: price, context and capabilities
Choose Claude Fable 5.1 for reused prompts and documents (RAG, agents), the hardest reasoning tasks, reasoning over long documents and the latest release; on the other points the two are level or the data is missing.
In short
- Both cost the same at the headline price ($20.00 / 1M tokens).
- Both accept 1M tokens per request.
- Claude Fable 5.1 is the newer model (September 2026, against June 2026).
Which should you choose?
Each answer below comes straight from the published prices, specifications and independent benchmark results.
Reused prompts and documents (RAG, agents)
Choose Claude Fable 5.1
Claude Fable 5.1 charges $0.25 per million cached input tokens, against $1.00 for Claude Fable 5.
Hardest reasoning tasks
Choose Claude Fable 5.1
Claude Fable 5.1 scores 53.4 on the Artificial Analysis Intelligence Index, against 49.6 for Claude Fable 5.
Reasoning over long documents
Choose Claude Fable 5.1
Claude Fable 5.1 scores 85.3% on Long-context reasoning (AA-LCR), against 82.3% for Claude Fable 5.
Latest release
Choose Claude Fable 5.1
Claude Fable 5.1 is the newer release (September 2026, against June 2026 for Claude Fable 5).
Monthly cost at three volumes
| Volume | Claude Fable 5 | Claude Fable 5.1 | Difference |
|---|---|---|---|
| Prototype: 1M input, 250K output tokens | $22.50 | $22.50 | = |
| Production: 20M input, 5M output tokens | $450.00 | $450.00 | = |
| Scale: 500M input, 100M output tokens | $10,000 | $10,000 | = |
Standard rates, without caching or batch discounts. Volumes are per month.
Specifications side by side
| Claude Fable 5 | Claude Fable 5.1 | |
|---|---|---|
| Provider | Anthropic | Anthropic |
| Category | Language models | Language models |
| Status | Legacy | Generally available |
| Headline price | $20.00 / 1M tokens | $20.00 / 1M tokens |
| Input | $10.00 / 1M tokens | $10.00 / 1M tokens |
| Output | $50.00 / 1M tokens | $50.00 / 1M tokens |
| Cached input | $1.00 / 1M tokens | $0.25 / 1M tokens |
| Context window | 1M | 1M |
| Max output | 128k | 128k |
| Released | June 2026 | September 2026 |
| Knowledge cutoff | No data | June 2026 |
| Licence | Proprietary | Proprietary |
| Capabilities | Vision, Reasoning, Tool calling, Structured output, Prompt caching, Batch API | Vision, Reasoning, Tool calling, Structured output, Prompt caching, Batch API |
| API model id | claude-fable-5 | claude-fable-5-1 |
Benchmarks side by side
Leader in bold.
| Benchmark | Claude Fable 5 | Claude Fable 5.1 |
|---|---|---|
| Intelligence Index | 49.6 | 53.4 |
| SciCode | 61% | 63.1% |
| GPQA Diamond | 92.6% | 93.7% |
| Humanity's Last Exam | 55.5% | 59.1% |
| Long-context reasoning (AA-LCR) | 82.3% | 85.3% |
| Terminal-Bench Hard | 62.9% | No data |
| IFBench (instruction following) | 63.5% | No data |
| τ²-Bench (agentic tool use) | 98.5% | No data |
Independent evaluations by Artificial Analysis, run the same way for every model, at the reasoning setting shown. Percentages unless marked as an index.
Frequently asked questions
Should I choose Claude Fable 5 or Claude Fable 5.1?
Choose Claude Fable 5.1 for reused prompts and documents (RAG, agents), the hardest reasoning tasks, reasoning over long documents and the latest release; on the other points the two are level or the data is missing.
Which is cheaper, Claude Fable 5 or Claude Fable 5.1?
Both cost the same at the headline price ($20.00 / 1M tokens).
Which has the larger context window, Claude Fable 5 or Claude Fable 5.1?
Both accept 1M tokens per request.
What is the difference between Claude Fable 5 and Claude Fable 5.1?
Claude Fable 5 is made by Anthropic and Claude Fable 5.1 by Anthropic. Both cost the same at the headline price ($20.00 / 1M tokens). Both accept 1M tokens per request. Claude Fable 5.1 is the newer model (September 2026, against June 2026).
How much do Claude Fable 5 and Claude Fable 5.1 cost per month?
At 20 million input and 5 million output tokens a month, Claude Fable 5 costs $450.00 and Claude Fable 5.1 costs $450.00, at standard rates.
Which is newer, Claude Fable 5 or Claude Fable 5.1?
Claude Fable 5.1 was released on September 2026 and Claude Fable 5 on June 2026.