Compare / Claude Haiku 4.5 vs Claude Sonnet 4
Claude Haiku 4.5 vs Claude Sonnet 4
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 Haiku 4.5 | Claude Sonnet 4 |
|---|---|---|---|
| Arena (formerly LMArena)reported | Business, management and financeArena rating | 1,420 | 1,387 |
| Arena (formerly LMArena)reported | Creative writingArena rating | 1,387 | 1,395 |
| Arena (formerly LMArena)reported | Expert promptsArena rating | 1,452 | 1,433 |
| Arena (formerly LMArena)reported | Instruction followingArena rating | 1,415 | 1,415 |
| Arena (formerly LMArena)reported | OverallArena rating | 1,414 | 1,402 |
| Arena (formerly LMArena)reported | Writing, literature and languageArena rating | 1,399 | 1,398 |
| UGI Leaderboardreported | Requested-length error% off the requested word count | 6.0% | 4.0% |
| UGI Leaderboardreported | Style adherencescore from 0 to 1 | 0.39 | 0.36 |
| UGI Leaderboardreported | Writing scorescore out of 100 | 52.2 | 63.7 |
| Vectara Hallucination Leaderboardreported | Answer rate% of documents | 99.5% | 98.6% |
| Vectara Hallucination Leaderboardreported | Hallucination rate% of summaries | 9.8% | 10.3% |
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.