Claude Fable 5.1 vs GPT-6 Astra
Claude Fable 5.1 is from Anthropic, released September 1, 2026. GPT-6 Astra is from OpenAI, released September 3, 2026.
- LMArena Elo1501 vs 1476. Claude Fable 5.1 is 1.7% ahead on LMArena Elo.
- Input per 1M$10 vs $10. Both $10 per million input tokens.
- Output per 1M$50 vs $50. Both $50 per million output tokens.
- Context window1M vs 1,050,000. GPT-6 Astra takes 4.8% more context in one request.
Prices are the vendors’ published API rates; Elo is LMArena’s text board. Each figure is dated on its model page.
Interactive Comparison
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$10 / $50 per 1M tokens | $10 / $50 per 1M tokens | |
|---|---|---|
| Identity | ||
| Developer | Anthropic | OpenAI |
| Released | Sep 2026 | Sep 2026 |
| Status | GA | GA |
| Licence | Proprietary | Proprietary |
| Self-hostable | No | No |
| Cost | ||
| Blended $/1M tokensinput × 0.75 + output × 0.25 | $20.000 / 1M tokens | $20.000 / 1M tokens |
| Input price | $10.000 / 1M tokens | $10.000 / 1M tokens |
| Output price | $50.000 / 1M tokens | $50.000 / 1M tokens |
| Cached input | $0.25 / 1M tokens (cache read, 2.5% of base input) | $1 per 1M tokens |
| Batch discount | 50% off (Batch API) | 50% (Batch and Flex) |
| Capacity | ||
| Context window | 1M tokens | 1,050,000 tokens |
| Max output | 128k tokens | 128k tokens |
| Capability | ||
| Vision in | Yes | Yes |
| Audio in | No | No |
| Extended reasoning | Adaptive thinking, always on; default effort high | — |
| Access | ||
| API | Yes | Yes |
| Chat app | Yes | Yes |
| Fine-tuning | No | — |
| Measured quality | ||
| LMArena Elo | 1501 (checked Oct 2026) | 1476 (checked Oct 2026) |
| LMArena rank | Rank 6 | Rank 30 |
| GPQA Diamond | — | 96 |
| Elo per dollarLMArena Elo ÷ blended $/1M tokens | 75 | 74 |
