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 5.1 vs GPT-6 Astra: price, context and capabilities
Choose Claude Fable 5.1 for reused prompts and documents (RAG, agents), reasoning over long documents and the most recent knowledge; 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).
- GPT-6 Astra reads more per request: 1.05M tokens against 1M.
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 GPT-6 Astra.
Hardest reasoning tasks
Either one
They are practically level on the Artificial Analysis Intelligence Index (53.4 and 52.7).
Reasoning over long documents
Choose Claude Fable 5.1
Claude Fable 5.1 scores 85.3% on Long-context reasoning (AA-LCR), against 80.7% for GPT-6 Astra.
Most recent knowledge
Choose Claude Fable 5.1
Claude Fable 5.1 was trained on data up to June 2026, against April 2026 for GPT-6 Astra.
Monthly cost at three volumes
| Volume | Claude Fable 5.1 | GPT-6 Astra | 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 5.1 | GPT-6 Astra | |
|---|---|---|
| Provider | Anthropic | OpenAI |
| Category | Language models | Language models |
| Status | Generally available | 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 | $0.25 / 1M tokens | $1.00 / 1M tokens |
| Context window | 1M | 1.05M |
| Max output | 128k | 128k |
| Released | September 2026 | Sep 3, 2026 |
| Knowledge cutoff | June 2026 | April 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-5-1 | gpt-6-astra |
Benchmarks side by side
Leader in bold.
| Benchmark | Claude Fable 5.1 | GPT-6 Astra |
|---|---|---|
| Intelligence Index | 53.4 | 52.7 |
| SciCode | 63.1% | 56.5% |
| GPQA Diamond | 93.7% | 96.1% |
| Humanity's Last Exam | 59.1% | 54.7% |
| Long-context reasoning (AA-LCR) | 85.3% | 80.7% |
| MMMU-Pro (visual reasoning) | No data | 86.9% |
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 5.1 or GPT-6 Astra?
Choose Claude Fable 5.1 for reused prompts and documents (RAG, agents), reasoning over long documents and the most recent knowledge; on the other points the two are level or the data is missing.
Which is cheaper, Claude Fable 5.1 or GPT-6 Astra?
Both cost the same at the headline price ($20.00 / 1M tokens).
Which has the larger context window, Claude Fable 5.1 or GPT-6 Astra?
GPT-6 Astra reads more per request: 1.05M tokens against 1M.
What is the difference between Claude Fable 5.1 and GPT-6 Astra?
Claude Fable 5.1 is made by Anthropic and GPT-6 Astra by OpenAI. Both cost the same at the headline price ($20.00 / 1M tokens). GPT-6 Astra reads more per request: 1.05M tokens against 1M.
How much do Claude Fable 5.1 and GPT-6 Astra cost per month?
At 20 million input and 5 million output tokens a month, Claude Fable 5.1 costs $450.00 and GPT-6 Astra costs $450.00, at standard rates.