Claude Opus 5.5 scores 72.4 on the Respan Index (#1), ahead of GPT-6.1 Sol at 69.4 (#4). Claude Opus 5.5 leads on 11 of the 22 benchmarks both report. GPT-6.1 Sol is 2.0x cheaper per token at list price. GPT-6.1 Sol has the larger context window (1.1M tokens).
* Estimated: no published scores in that category. How the Respan Index works
| Furniture Assembly (Epoch AI) |
| 83.3% |
| 80% |
| GPQA Diamond | 90.6% | 95.4% |
| LiveBench Agentic Coding (LiveBench) | 71.7% | 56.8% |
| LiveBench Coding (LiveBench) | 89.3% | 80.7% |
| LiveBench Data Analysis (LiveBench) | 80.3% | 82.7% |
| LiveBench Instruction Following (LiveBench) | 67% | 74.2% |
| LiveBench Language (LiveBench) | 86.3% | 90.1% |
| LiveBench Mathematics (LiveBench) | 97.1% | 96.8% |
| LiveBench Reasoning (LiveBench) | 92.2% | 92.6% |
| Mystery Game Puzzles (Epoch AI) | 71% | 80% |
| OTIS Mock AIME 2024-2025 (Epoch AI) | 100% | 100% |
| SAGE (Vals AI) | 45.8% | 46.5% |
| SimpleQA Verified | 72.2% | 73.9% |
| Terminal-Bench 4.0 (Vals AI) | 65.2% | 55.1% |
| LMArena Agent (LMArena) | 0.1382 | 0.1123 |
| LMArena Elo | 1504 | 1483 |
| LMArena WebDev (LMArena) | 1815 | 1758 |
| SimpleBench (SimpleBench) | 88.4% | 82.9% |
Higher is better. Each score links to where it was published.