Claude Sonnet 4.5 scores 29.1 on the Respan Index (#65), ahead of Claude Opus 4.1 at 29.0 (#67). Claude Sonnet 4.5 leads on 9 of the 14 benchmarks both report. Claude Sonnet 4.5 is 5.0x cheaper per token at list price.
* Estimated: no published scores in that category. How the Respan Index works
| GPQA Diamond |
| 77.3% |
| 83.4% |
| Mystery Game Puzzles (Epoch AI) | 21% | 17% |
| OTIS Mock AIME 2024-2025 (Epoch AI) | 68.9% | 77.8% |
| SAGE (Vals AI) | 31.4% | 36.1% |
| SimpleBench (SimpleBench) | 60% | 54.3% |
| SWE-bench Verified (Epoch AI) | 73.3% | 71.3% |
| WeirdML (Håvard Tveit Ihle) | 45.9% | 47.7% |
| LMArena Elo | 1450 | 1457 |
| LMArena WebDev (LMArena) | 1389 | 1393 |
| SWE-bench Verified | 74.5% | 77.2% |
Higher is better. Each score links to where it was published.