Claude Fable 5.1 vs Claude Opus 4.1
Claude Fable 5.1 is cheaper on output tokens, while Claude Fable 5.1 offers a larger context window. Choose Claude Fable 5.1 or Claude Opus 4.1 based on the trade-off between cost, context, and the benchmarks that matter for your use case.
| Spec | Claude Fable 5.1 | Claude Opus 4.1 |
|---|---|---|
| Provider | Anthropic | Anthropic |
| Input / 1M tokens | $10.00 | $15.00 |
| Output / 1M tokens | $50.00 | $75.00 |
| Context window | 1M | 200K |
| Parameters | — | — |
| Open weights | — | No |
| Released | — | Aug 2025 |
| Epoch Capabilities Index score | 166 | 144 |
| LMArena (Chatbot Arena) Elo score | 1514 | 1419 |
| LMArena WebDev Elo score | 1746 | 1390 |
| LMArena Vision Elo score | 1319 | — |
| FrontierMath score | — | 7.2 |
| GPQA Diamond score | — | 77.3 |
FAQ
Is Claude Fable 5.1 or Claude Opus 4.1 cheaper?
Claude Fable 5.1 is cheaper on output tokens ($50.00 vs $75.00 per 1M).
Which has the larger context window, Claude Fable 5.1 or Claude Opus 4.1?
Claude Fable 5.1 has the larger context window (1M tokens).
Pricing is indicative — confirm with the provider before production use. Highlighted values indicate the better figure for that row.