Compare / Claude Sonnet 4 vs GPT-5.1
Claude Sonnet 4 vs GPT-5.1
11 results from 3 sources that measured both models. Each row is in the source's own units; there is no overall winner.
| Benchmark | Metric | Claude Sonnet 4 | GPT-5.1 |
|---|---|---|---|
| Arena (formerly LMArena)reported | Business, management and financeArena rating | 1,387 | 1,448 |
| Arena (formerly LMArena)reported | Creative writingArena rating | 1,395 | 1,428 |
| Arena (formerly LMArena)reported | Expert promptsArena rating | 1,433 | 1,482 |
| Arena (formerly LMArena)reported | Instruction followingArena rating | 1,415 | 1,450 |
| Arena (formerly LMArena)reported | OverallArena rating | 1,402 | 1,456 |
| Arena (formerly LMArena)reported | Writing, literature and languageArena rating | 1,398 | 1,437 |
| UGI Leaderboardreported | Requested-length error% off the requested word count | 4.0% | 113.0% |
| UGI Leaderboardreported | Style adherencescore from 0 to 1 | 0.36 | 0.38 |
| UGI Leaderboardreported | Writing scorescore out of 100 | 63.7 | 55.8 |
| Vectara Hallucination Leaderboardreported | Answer rate% of documents | 98.6% | 100.0% |
| Vectara Hallucination Leaderboardreported | Hallucination rate% of summaries | 10.3% | 10.9% |
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.