GPT-5.6 Luna vs GPT-6 Astra
GPT-5.6 Luna Verdict
- GPT-6 Astra (max) leads on quality: 70.9 vs 59.4.
- GPT-5.6 Luna (xhigh) is stronger in human preference, long context, multimodal.
- GPT-6 Astra (max) is stronger in agents & tools, coding, knowledge, reasoning, maths.
- GPT-5.6 Luna (xhigh) is 44× cheaper ($0.450 vs $20.00 per 1M blended).
- GPT-5.6 Luna (xhigh) streams 4.0× faster (107 vs 27 tokens per second).
| Metric | GPT-5.6 Luna (xhigh) | GPT-6 Astra (max) |
|---|---|---|
| BenchLeader Index | 59.4 | 70.9 |
| Agents & tools score | 50.1 | 68.2 |
| Coding score | 60.0 | 78.6 |
| Composite score | 72.9 | 72.9 |
| Human preference score | 65.0 | – |
| Knowledge score | 59.0 | 80.0 |
| Long context score | 67.4 | – |
| Multimodal score | 61.6 | – |
| Reasoning score | 53.9 | 73.6 |
| Maths score | – | 77.2 |
| Blended price $/M | $0.450 | $20.00 |
| Output speed | 107 tok/s | 27 tok/s |
| Time to first answer | 55.4 s | 337.3 s |
| Context window | 1M | 1.1M |
| GPQA Diamond | – | 95.8% |
| FrontierMath Tiers 1–3 | – | 93.7% |
| FrontierMath Tier 4 | – | 97.6% |
| OTIS Mock AIME | – | 100.0% |
| SimpleQA Verified | – | 75.6% |
| Terminal-Bench | – | 58.2% |
| SimpleBench | 46.8% | – |
| SciCode | 50.0% | 56.5% |
| FrontierCode | – | 53.3% |
| LMArena Text | 1453 | – |
| LMArena Hard Prompts | 1473 | – |
| LMArena Coding | 1497 | – |
| LMArena WebDev | 1520 | 1796 |
| LMArena Vision | 1254 | – |
| LMArena Agent | 1.1 | 12.5 |
| LiveBench | – | 82.2% |
| LiveBench Reasoning | – | 92.7% |
| LiveBench Coding | – | 80.4% |
| LiveBench Agentic Coding | – | 57.3% |
| LiveBench Mathematics | – | 96.8% |
| LiveBench Data Analysis | – | 83.0% |
| LiveBench Language | – | 89.4% |
| AA Intelligence Index | 34.8 | – |
| AA-LCR | 81.7% | – |
| MMMU-Pro | 78.5% | – |
| AA-Omniscience | -10.8 | – |
| GPQA Diamond (AA) | 89.5% | – |
| Humanity's Last Exam (AA) | 37.0% | – |
| SciCode (AA) | 50.5% | – |
| Terminal-Bench 2.1 (Vals) | – | 87.3% |
| Vals Index | – | 66.6 |
| ARC-AGI-1 | 87.7% | 97.5% |
| ARC-AGI-2 | 47.6% | 95.0% |
| ARC-AGI-3 | 0.0% | 98.6% |
Data as of 2026-09-10. Best configuration of each model; every score links to its source on the model pages.
GPT-5.6 Luna vs GPT-6 Astra: questions
- Is GPT-5.6 Luna better than GPT-6 Astra?
- GPT-6 Astra (max) leads on quality: 70.9 vs 59.4. The BenchLeader Index combines every independent quality benchmark; GPT-6 Astra (max) is ahead overall as of 2026-09-10, but check the category scores for your use.
- Is GPT-5.6 Luna better than GPT-6 Astra for coding?
- GPT-6 Astra scores higher in coding (79 vs 60 on the category index, where 50 is average).
- Is GPT-5.6 Luna better than GPT-6 Astra for agentic tasks?
- GPT-6 Astra scores higher in agentic tasks (68 vs 50 on the category index, where 50 is average).
- Which is cheaper, GPT-5.6 Luna or GPT-6 Astra?
- GPT-5.6 Luna is cheaper: $0.450 against $20.00 per million tokens, blended at three input tokens per output token.
- Which is faster, GPT-5.6 Luna or GPT-6 Astra?
- GPT-5.6 Luna streams faster: 107 against 27 output tokens per second.
- Which has the larger context window?
- GPT-6 Astra accepts more context: 1.1M against 1M tokens.