Claude Opus 5.5 vs GPT-6 Luna
Claude Opus 5.5 
GPT-6 Luna Verdict
- Claude Opus 5.5 (thinking) leads on quality: 70.5 vs 61.2.
- Claude Opus 5.5 (thinking) is stronger in composite, knowledge, long context, multimodal, reasoning.
- GPT-6 Luna (max) is 40× cheaper ($0.200 vs $8.00 per 1M blended).
- GPT-6 Luna (max) streams 3.2× faster (157 vs 50 tokens per second).
| Metric | Claude Opus 5.5 (thinking) | GPT-6 Luna (max) |
|---|---|---|
| BenchLeader Index | 70.5 | 61.2 |
| Composite score | 95.0 | 73.9 |
| Knowledge score | 84.4 | 63.2 |
| Long context score | 68.2 | 67.5 |
| Multimodal score | 71.7 | 59.2 |
| Reasoning score | 95.0 | 76.1 |
| Blended price $/M | $8.00 | $0.200 |
| Output speed | 50 tok/s | 157 tok/s |
| Time to first answer | 4.3 s | 142.6 s |
| Context window | 1M | 1.1M |
| AA Intelligence Index | 57.6 | 37.3 |
| AA-LCR | 84.7% | 83.3% |
| MMMU-Pro | 87.7% | 75.5% |
| AA-Omniscience | 46.4 | 0.7 |
| Humanity's Last Exam (AA) | 61.4% | 38.5% |
| SciCode (AA) | 66.9% | 54.6% |
| CritPt | 31.7% | 19.4% |
| GDPval (AA) | 67.3% | 43.4% |
| Terminal-Bench 4.0 (AA) | 59.6% | 12.6% |
| AutomationBench | 69.5% | 53.2% |
| GDP.pdf | 26.2% | 20.4% |
| MLCR | – | 16.1% |
| Harvey LAB | 91.2% | – |
| AA-Omniscience: accuracy | 66.2% | 43.8% |
| AA-Omniscience: non-hallucination | 41.4% | 23.3% |
| AA-Briefcase | 1822 | 1299 |
Data as of 2026-09-23. Best configuration of each model; every score links to its source on the model pages.
Claude Opus 5.5 vs GPT-6 Luna: questions
- Is Claude Opus 5.5 better than GPT-6 Luna?
- Claude Opus 5.5 (thinking) leads on quality: 70.5 vs 61.2. The BenchLeader Index combines every independent quality benchmark; Claude Opus 5.5 (thinking) is ahead overall as of 2026-09-23, but check the category scores for your use.
- Which is cheaper, Claude Opus 5.5 or GPT-6 Luna?
- GPT-6 Luna is cheaper: $0.200 against $8.00 per million tokens, blended at three input tokens per output token.
- Which is faster, Claude Opus 5.5 or GPT-6 Luna?
- GPT-6 Luna streams faster: 157 against 50 output tokens per second.
- Which has the larger context window?
- GPT-6 Luna accepts more context: 1.1M against 1M tokens.