Claude Fable 5.1 vs Claude Opus 5.5
Claude Fable 5.1 Verdict
- Claude Fable 5.1 (xhigh) and Claude Opus 5.5 (thinking) are level on quality (71.1 vs 70.7).
- Claude Fable 5.1 (xhigh) is stronger in agents & tools, coding.
- Claude Opus 5.5 (thinking) is stronger in composite, knowledge, long context, reasoning, multimodal.
- Claude Opus 5.5 (thinking) is 2.5× cheaper ($8.00 vs $20.00 per 1M blended).
| Metric | Claude Fable 5.1 (xhigh) | Claude Opus 5.5 (thinking) |
|---|---|---|
| BenchLeader Index | 71.1 | 70.7 |
| Agents & tools score | 68.0 | – |
| Coding score | 71.4 | – |
| Composite score | 94.1 | 95.0 |
| Knowledge score | 83.1 | 85.0 |
| Long context score | 67.7 | 68.5 |
| Reasoning score | 80.4 | 95.0 |
| Multimodal score | – | 71.9 |
| Blended price $/M | $20.00 | $8.00 |
| Output speed | 61 tok/s | 48 tok/s |
| Time to first answer | 164.8 s | 4.2 s |
| Context window | 1M | 1M |
| Humanity's Last Exam | 46.5% | – |
| Terminal-Bench | 57.9% | – |
| SciCode | 60.9% | – |
| AA Intelligence Index | 53.2 | 57.6 |
| AA-LCR | 83.0% | 84.7% |
| MMMU-Pro | – | 87.7% |
| AA-Omniscience | 42.4 | 46.4 |
| GPQA Diamond (AA) | 93.4% | – |
| Humanity's Last Exam (AA) | 58.7% | 61.4% |
| SciCode (AA) | 60.9% | 66.9% |
| ARC-AGI-1 | 96.5% | – |
| ARC-AGI-2 | 90.0% | – |
| CritPt | 31.1% | 31.7% |
| GDPval (AA) | 61.0% | 67.3% |
| τ²-Bench Banking (AA) | 45.8% | – |
| SWE Atlas: Codebase QnA | 60.0% | – |
| SWE Atlas: Refactoring | 56.7% | – |
| SWE Atlas: Test Writing | 67.0% | – |
| LMCA | 65.1% | – |
| DTBench | 97.6% | – |
| CursorBench | 51.6% | – |
| Terminal-Bench 4.0 (AA) | 55.0% | 59.6% |
| Terminal-Bench 2.1 (AA) | 91.0% | – |
| AutomationBench | 57.8% | 69.5% |
| GDP.pdf | 26.2% | 26.2% |
| Harvey LAB | 93.3% | 91.2% |
| AA-Omniscience: accuracy | 66.2% | 66.2% |
| AA-Omniscience: non-hallucination | 29.4% | 41.4% |
| AA-Briefcase | 1669 | 1822 |
Data as of 2026-09-22. Best configuration of each model; every score links to its source on the model pages.
Claude Fable 5.1 vs Claude Opus 5.5: questions
- Is Claude Fable 5.1 better than Claude Opus 5.5?
- Claude Fable 5.1 (xhigh) and Claude Opus 5.5 (thinking) are level on quality (71.1 vs 70.7). The BenchLeader Index combines every independent quality benchmark; Claude Fable 5.1 (xhigh) is ahead overall as of 2026-09-22, but check the category scores for your use.
- Which is cheaper, Claude Fable 5.1 or Claude Opus 5.5?
- Claude Opus 5.5 is cheaper: $8.00 against $20.00 per million tokens, blended at three input tokens per output token.
- Which is faster, Claude Fable 5.1 or Claude Opus 5.5?
- Claude Fable 5.1 streams faster: 61 against 48 output tokens per second.
- Which has the larger context window?
- Both accept 1M tokens of context.