Claude Fable 5.1 vs GPT-6 Astra
Claude Fable 5.1 (Anthropic) and GPT-6 Astra (OpenAI) compared on price, context window, speed and independent benchmarks. Claude Fable 5.1 scores higher on the Artificial Analysis Intelligence Index (65.7 vs 61.2), while GPT-6 Astra is 1.0× cheaper on a blended basis. Pick Claude Fable 5.1 for the hardest tasks and GPT-6 Astra when cost dominates.
| Claude Fable 5.1 | GPT-6 Astra | |
|---|---|---|
| Provider | Anthropic | OpenAI |
| Input $/1M | $10.0 | $10.0 |
| Output $/1M | $50.0 | $50.0 |
| Blended $/1M (3:1) | $20.0 | $20.0 |
| Cached input $/1M | $0.25 | $1.00 |
| Context window | 1M | 1.1M |
| Knowledge cutoff | 2026-06 | 2026-04 |
| License | proprietary | proprietary |
| Speed (tok/s) | 71 | — |
| Artificial Analysis Intelligence Index | 65.7 | 61.2 |
| GPQA Diamond | 93.7% | 96.1% |
| Humanity's Last Exam | 59.1% | 54.7% |