Claude 4.5 Opus vs Claude Fable 5.1
Claude 4.5 Opus is cheaper on output tokens, while Claude Fable 5.1 offers a larger context window. Choose Claude 4.5 Opus or Claude Fable 5.1 based on the trade-off between cost, context, and the benchmarks that matter for your use case.
| Spec | Claude 4.5 Opus | Claude Fable 5.1 |
|---|---|---|
| Provider | AI/ML API | Anthropic |
| Input / 1M tokens | $6.88 | $10.00 |
| Output / 1M tokens | $34.39 | $50.00 |
| Context window | 200K | 1M |
| Parameters | — | — |
| Open weights | No | — |
| Released | Nov 2025 | — |
| SWE-bench Verified score | 76.8 | — |
| LMArena (Chatbot Arena) Elo score | — | 1510 |
| LMArena WebDev Elo score | — | 1743 |
| LMArena Vision Elo score | — | 1318 |
| Epoch Capabilities Index score | — | 165 |
FAQ
Is Claude 4.5 Opus or Claude Fable 5.1 cheaper?
Claude 4.5 Opus is cheaper on output tokens ($34.39 vs $50.00 per 1M).
Which has the larger context window, Claude 4.5 Opus or Claude Fable 5.1?
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.