Claude Fable 5.1 vs Claude Opus 5
Claude Fable 5.1 (Anthropic) and Claude Opus 5 (Anthropic) compared on price, context window, speed and independent benchmarks. Claude Fable 5.1 scores higher on the Artificial Analysis Intelligence Index (65.7 vs 63.1), while Claude Opus 5 is 2.0× cheaper on a blended basis. Pick Claude Fable 5.1 for the hardest tasks and Claude Opus 5 when cost dominates.
| Claude Fable 5.1 | Claude Opus 5 | |
|---|---|---|
| Provider | Anthropic | Anthropic |
| Input $/1M | $10.0 | $5.00 |
| Output $/1M | $50.0 | $25.0 |
| Blended $/1M (3:1) | $20.0 | $10.0 |
| Cached input $/1M | $0.25 | $0.50 |
| Context window | 1M | 1M |
| Knowledge cutoff | 2026-06 | 2026-05 |
| License | proprietary | proprietary |
| Speed (tok/s) | 71 | 52 |
| Artificial Analysis Intelligence Index | 65.7 | 63.1 |
| LMArena Elo | — | 1505 |
| GPQA Diamond | 93.7% | 93.2% |
| SWE-bench Verified | — | 97% |
| LiveCodeBench | — | 74.6% |
| MMLU-Pro | — | 91.6% |
| Humanity's Last Exam | 59.1% | 54.9% |