Claude Fable 5.1 vs Claude Sonnet 4.5
Claude Fable 5.1 Verdict
- Claude Fable 5.1 (max) leads on quality: 70.1 vs 57.9.
- Claude Fable 5.1 (max) is stronger in agents & tools, coding, composite, human preference, knowledge, maths, reasoning.
- Claude Sonnet 4.5 (high) is 3.3× cheaper ($6.00 vs $20.00 per 1M blended).
- Claude Fable 5.1 (max) streams 1.7× faster (67 vs 40 tokens per second).
| Metric | Claude Fable 5.1 (max) | Claude Sonnet 4.5 (high) |
|---|---|---|
| BenchLeader Index | 70.1 | 57.9 |
| Agents & tools score | 67.2 | – |
| Coding score | 78.1 | 56.4 |
| Composite score | 76.6 | – |
| Human preference score | 70.8 | 65.3 |
| Knowledge score | 75.9 | – |
| Maths score | 77.0 | – |
| Reasoning score | 71.8 | 66.4 |
| Blended price $/M | $20.00 | $6.00 |
| Output speed | 67 tok/s | 40 tok/s |
| Time to first answer | 258.6 s | 1.2 s |
| Context window | 1M | 1M |
| FrontierMath Tiers 1–3 | 90.2% | – |
| FrontierMath Tier 4 | 87.8% | – |
| OTIS Mock AIME | 100.0% | – |
| SimpleQA Verified | 70.8% | – |
| Terminal-Bench | 57.9% | – |
| SciCode | 62.0% | – |
| WeirdML | 92.9% | – |
| ProofBench | 100.0% | – |
| LMArena Text | 1501 | 1456 |
| LMArena Hard Prompts | 1519 | 1487 |
| LMArena Coding | 1519 | 1520 |
| LMArena WebDev | 1758 | 1393 |
| LMArena Agent | 13.9 | – |
| LiveBench | 83.4% | – |
| LiveBench Reasoning | 91.7% | – |
| LiveBench Coding | 86.4% | – |
| LiveBench Agentic Coding | 66.1% | – |
| LiveBench Mathematics | 97.0% | – |
| LiveBench Data Analysis | 80.3% | – |
| LiveBench Language | 89.5% | – |
| SWE-bench Verified (bash only) | – | 71.4% |
| ARC-AGI-1 | 97.5% | – |
| ARC-AGI-2 | 90.0% | – |
Data as of 2026-09-13. Best configuration of each model; every score links to its source on the model pages.
Claude Fable 5.1 vs Claude Sonnet 4.5: questions
- Is Claude Fable 5.1 better than Claude Sonnet 4.5?
- Claude Fable 5.1 (max) leads on quality: 70.1 vs 57.9. The BenchLeader Index combines every independent quality benchmark; Claude Fable 5.1 (max) is ahead overall as of 2026-09-13, but check the category scores for your use.
- Is Claude Fable 5.1 better than Claude Sonnet 4.5 for coding?
- Claude Fable 5.1 scores higher in coding (78 vs 56 on the category index, where 50 is average).
- Which is cheaper, Claude Fable 5.1 or Claude Sonnet 4.5?
- Claude Sonnet 4.5 is cheaper: $6.00 against $20.00 per million tokens, blended at three input tokens per output token.
- Which is faster, Claude Fable 5.1 or Claude Sonnet 4.5?
- Claude Fable 5.1 streams faster: 67 against 40 output tokens per second.
- Which has the larger context window?
- Both accept 1M tokens of context.