Compare / Claude Opus 4.8 vs GPT-5.6 Luna
Claude Opus 4.8 vs GPT-5.6 Luna
27 results from 6 sources that measured both models. Each row is in the source's own units; there is no overall winner.
| Benchmark | Metric | Claude Opus 4.8 | GPT-5.6 Luna |
|---|---|---|---|
| Arena (formerly LMArena)reported | Confirmed task successIPS effect estimate | 0.04 | -0.05 |
| Arena (formerly LMArena)reported | Praise over complaintIPS effect estimate | 0.15 | -0.04 |
| Arena (formerly LMArena)reported | SteerabilityIPS effect estimate | 0.10 | 0.02 |
| Arena (formerly LMArena)reported | Tool groundingIPS effect estimate | -0.00 | 0.00 |
| Arena (formerly LMArena)reported | OverallArena rating | 1,486 | 1,462 |
| Arena (formerly LMArena)reported | OverallArena rating | 1,469 | 1,461 |
| Arena (formerly LMArena)reported | Business, management and financeArena rating | 1,490 | 1,463 |
| Arena (formerly LMArena)reported | Creative writingArena rating | 1,467 | 1,412 |
| Arena (formerly LMArena)reported | Expert promptsArena rating | 1,525 | 1,491 |
| Arena (formerly LMArena)reported | Instruction followingArena rating | 1,491 | 1,446 |
| Arena (formerly LMArena)reported | OverallArena rating | 1,480 | 1,454 |
| Arena (formerly LMArena)reported | Writing, literature and languageArena rating | 1,474 | 1,435 |
| Artificial Analysisreported | Artificial Analysis Coding Indexindex score | 74.3 | 71.4 |
| Artificial Analysisreported | Artificial Analysis Intelligence Indexindex score | 41.8 | 37.3 |
| Artificial Analysisreported | GPQA Diamond% of questions | 92.0% | 91.1% |
| Artificial Analysisreported | Humanity's Last Exam% of questions | 48.7% | 39.5% |
| Artificial Analysisreported | Long-context reasoning (AA-LCR)% of questions | 77.7% | 83.7% |
| Artificial Analysisreported | SciCode% of problems | 54.4% | 53.6% |
| Artificial Analysisreported | Terminal-Bench 2.1% of tasks | 84.6% | 80.9% |
| Artificial Analysisreported | Terminal-Bench 4.0% of tasks | 21.7% | 11.6% |
| Artificial Analysisreported | Τ-bench banking% of tasks | 34.2% | 31.1% |
| GDP.pdfreported | Professional document tasks% of rubric | 24.0% | 22.7% |
| SimpleQA Verified (Epoch AI)reported | Correct answers% of questions | 53.0% | 41.0% |
| UGI Leaderboardreported | Requested-length error% off the requested word count | 6.0% | 15.0% |
| UGI Leaderboardreported | Style adherencescore from 0 to 1 | 0.40 | 0.38 |
| UGI Leaderboardreported | Writing scorescore out of 100 | 65.9 | 53.7 |
| Vending-Bench 2reported | Money after a yearUS dollars | $5,787.43 | $4,094.71 |
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.