Compare / Claude Fable 5.1 vs Claude Opus 4.5
Claude Fable 5.1 vs Claude Opus 4.5
18 results from 6 sources that measured both models. Each row is in the source's own units; there is no overall winner.
| Benchmark | Metric | Claude Fable 5.1 | Claude Opus 4.5 |
|---|---|---|---|
| Arena (formerly LMArena)reported | OverallArena rating | 1,493 | 1,465 |
| Arena (formerly LMArena)reported | OverallArena rating | 1,501 | 1,459 |
| Arena (formerly LMArena)reported | Business, management and financeArena rating | 1,485 | 1,472 |
| Arena (formerly LMArena)reported | Creative writingArena rating | 1,484 | 1,469 |
| Arena (formerly LMArena)reported | Expert promptsArena rating | 1,516 | 1,503 |
| Arena (formerly LMArena)reported | Instruction followingArena rating | 1,497 | 1,483 |
| Arena (formerly LMArena)reported | OverallArena rating | 1,501 | 1,474 |
| Arena (formerly LMArena)reported | Writing, literature and languageArena rating | 1,496 | 1,467 |
| Artificial Analysisreported | Artificial Analysis Intelligence Indexindex score | 53.4 | 29.1 |
| Artificial Analysisreported | GPQA Diamond% of questions | 93.7% | 86.6% |
| Artificial Analysisreported | Humanity's Last Exam% of questions | 59.1% | 30.1% |
| Artificial Analysisreported | Long-context reasoning (AA-LCR)% of questions | 85.3% | 77.3% |
| Remote Labor Indexreported | Projects done to client standard% of projects | 17.9% | 3.8% |
| SimpleQA Verified (Epoch AI)reported | Correct answers% of questions | 70.8% | 45.7% |
| UGI Leaderboardreported | Requested-length error% off the requested word count | 3.0% | 3.0% |
| UGI Leaderboardreported | Style adherencescore from 0 to 1 | 0.43 | 0.39 |
| UGI Leaderboardreported | Writing scorescore out of 100 | 63.9 | 70.4 |
| Vending-Bench 2reported | Money after a yearUS dollars | $5,421.56 | $4,967.06 |
Bold green marks the better value on that metric. Where a source reports ranges that overlap, the difference may not be meaningful; see the benchmark page for ranges.