Compare / Claude Opus 4.5 vs Claude Opus 5.5
Claude Opus 4.5 vs Claude Opus 5.5
13 results from 4 sources that measured both models. Each row is in the source's own units; there is no overall winner.
| Benchmark | Metric | Claude Opus 4.5 | Claude Opus 5.5 |
|---|---|---|---|
| Arena (formerly LMArena)reported | Business, management and financeArena rating | 1,472 | 1,499 |
| Arena (formerly LMArena)reported | Creative writingArena rating | 1,469 | 1,521 |
| Arena (formerly LMArena)reported | Expert promptsArena rating | 1,503 | 1,556 |
| Arena (formerly LMArena)reported | Instruction followingArena rating | 1,483 | 1,516 |
| Arena (formerly LMArena)reported | OverallArena rating | 1,474 | 1,509 |
| Arena (formerly LMArena)reported | Writing, literature and languageArena rating | 1,467 | 1,520 |
| Artificial Analysisreported | Artificial Analysis Intelligence Indexindex score | 29.1 | 57.6 |
| Artificial Analysisreported | Humanity's Last Exam% of questions | 30.1% | 61.4% |
| Artificial Analysisreported | Long-context reasoning (AA-LCR)% of questions | 77.3% | 84.7% |
| SimpleQA Verified (Epoch AI)reported | Correct answers% of questions | 45.7% | 72.2% |
| UGI Leaderboardreported | Requested-length error% off the requested word count | 3.0% | 2.0% |
| UGI Leaderboardreported | Style adherencescore from 0 to 1 | 0.39 | 0.43 |
| UGI Leaderboardreported | Writing scorescore out of 100 | 70.4 | 70.0 |
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.