Claude Opus 5.5 scores 72.4 on the Respan Index (#1), ahead of GPT-5.5 at 52.5 (#15). Claude Opus 5.5 leads on 17 of the 22 benchmarks both report. Claude Opus 5.5 is 1.4x cheaper per token at list price.
* Estimated: no published scores in that category. How the Respan Index works
| Furniture Assembly (Epoch AI) |
| 83.3% |
| 44.2% |
| GPQA Diamond | 90.6% | 90.7% |
| LiveBench Agentic Coding (LiveBench) | 71.7% | 54% |
| LiveBench Coding (LiveBench) | 89.3% | 82.1% |
| LiveBench Data Analysis (LiveBench) | 80.3% | 81.6% |
| LiveBench Instruction Following (LiveBench) | 67% | 70.7% |
| LiveBench Language (LiveBench) | 86.3% | 87.4% |
| LiveBench Mathematics (LiveBench) | 97.1% | 95.9% |
| LiveBench Reasoning (LiveBench) | 92.2% | 89.7% |
| MirrorCode (Epoch AI) | 77.4% | 10% |
| Mystery Game Puzzles (Epoch AI) | 71% | 56% |
| OTIS Mock AIME 2024-2025 (Epoch AI) | 100% | 84.4% |
| SAGE (Vals AI) | 45.8% | 51.5% |
| SimpleQA Verified | 72.2% | 63% |
| Vending-Bench 2 (Andon Labs) | 9235.25 | 7523.84 |
| LMArena Agent (LMArena) | 0.1382 | 0.0415 |
| LMArena Elo | 1504 | 1466 |
| SimpleBench (SimpleBench) | 88.4% | 69% |
Higher is better. Each score links to where it was published.