Claude Opus 5.5 vs GPT-6 Astra
Claude Opus 5.5 
GPT-6 Astra Verdict
- GPT-6 Astra (max) leads on quality: 71.7 vs 70.7.
- Claude Opus 5.5 (thinking) is stronger in composite, knowledge, long context, multimodal, reasoning.
- GPT-6 Astra (max) is stronger in agents & tools, coding, human preference, maths.
- Claude Opus 5.5 (thinking) is 2.5× cheaper ($8.00 vs $20.00 per 1M blended).
| Metric | Claude Opus 5.5 (thinking) | GPT-6 Astra (max) |
|---|---|---|
| BenchLeader Index | 70.7 | 71.7 |
| Composite score | 95.0 | 83.1 |
| Knowledge score | 85.0 | 81.7 |
| Long context score | 68.5 | 66.5 |
| Multimodal score | 71.9 | 66.9 |
| Reasoning score | 95.0 | 77.7 |
| Agents & tools score | – | 68.6 |
| Coding score | – | 77.6 |
| Human preference score | – | 68.2 |
| Maths score | – | 76.9 |
| Blended price $/M | $8.00 | $20.00 |
| Output speed | 48 tok/s | 61 tok/s |
| Time to first answer | 4.2 s | 322.6 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% |
| SciCode | – | 56.5% |
| WeirdML | – | 93.3% |
| FrontierCode | – | 53.3% |
| LMArena Text | – | 1480 |
| LMArena Hard Prompts | – | 1497 |
| LMArena Coding | – | 1543 |
| LMArena WebDev | – | 1800 |
| LMArena Vision | – | 1279 |
| LMArena Agent | – | 11.5 |
| 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% |
| LiveBench Instruction Following | – | 75.6% |
| AA Intelligence Index | 57.6 | 52.7 |
| AA-LCR | 84.7% | 80.7% |
| MMMU-Pro | 87.7% | 86.9% |
| AA-Omniscience | 46.4 | 43.4 |
| GPQA Diamond (AA) | – | 96.1% |
| Humanity's Last Exam (AA) | 61.4% | 54.7% |
| SciCode (AA) | 66.9% | 56.5% |
| IOI | – | 100.0% |
| Terminal-Bench 2.1 (Vals) | – | 87.3% |
| Vals Index | – | 66.6 |
| ARC-AGI-1 | – | 97.5% |
| ARC-AGI-2 | – | 95.0% |
| ARC-AGI-3 | – | 98.6% |
| CritPt | 31.7% | 31.7% |
| GDPval (AA) | 67.3% | 52.1% |
| τ²-Bench Banking (AA) | – | 41.4% |
| Analyst Agent (AA) | – | 51.3% |
| BioMysteryBench | – | 79.3% |
| Code Migration | – | 67.7% |
| CUA-bench | – | 19.2% |
| CyberBench | – | 41.1% |
| Excel Modeling Benchmark | – | 71.7% |
| Finance Agent v2 | – | 53.5% |
| Harvey's Legal Agent Benchmark | – | 5.4% |
| Legal Research Bench | – | 39.4% |
| MedCode | – | 48.5% |
| MedScribe | – | 87.9% |
| MysteryMechanism | – | 53.1% |
| ProgramBench | – | 5.5% |
| SAGE | – | 46.4% |
| SREBench | – | 56.9% |
| Tax Agent Bench | – | 63.3% |
| Terminal-Bench 4.0 (Vals) | – | 57.1% |
| Terminal-Bench Science | – | 65.7% |
| Time Horizon Index: KSP | – | 90.5% |
| Vibe Code Bench 1-100 | – | 27.6% |
| Vibe Code Bench v1.1 | – | 89.6% |
| DrugDiscoveryBench | – | 68.7% |
| LMArena Creative Writing | – | 1461 |
| LMArena Instruction Following | – | 1461 |
| LMArena Multi-turn | – | 1499 |
| LMArena Longer Queries | – | 1481 |
| LMArena Document | – | 1473 |
| Chess Puzzles | – | 72.0% |
| EBR-bench | – | 76.2% |
| Mystery Game Puzzles | – | 84.0% |
| BALROG | – | 68.3% |
| DeepSWE | – | 73.2% |
| ALE-Bench | – | 2951.3 |
| FrontierSWE | – | 65.5% |
| Terminal-Bench 4.0 (AA) | 59.6% | 59.1% |
| Terminal-Bench 2.1 (AA) | – | 88.4% |
| AutomationBench | 69.5% | 68.5% |
| GDP.pdf | 26.2% | 31.0% |
| MLCR | – | 35.0% |
| Harvey LAB | 91.2% | – |
| AA-Omniscience: accuracy | 66.2% | 62.6% |
| AA-Omniscience: non-hallucination | 41.4% | 48.7% |
| AA-Briefcase | 1822 | 1569 |
Data as of 2026-09-22. Best configuration of each model; every score links to its source on the model pages.
Claude Opus 5.5 vs GPT-6 Astra: questions
- Is Claude Opus 5.5 better than GPT-6 Astra?
- GPT-6 Astra (max) leads on quality: 71.7 vs 70.7. The BenchLeader Index combines every independent quality benchmark; GPT-6 Astra (max) is ahead overall as of 2026-09-22, but check the category scores for your use.
- Which is cheaper, Claude Opus 5.5 or GPT-6 Astra?
- Claude Opus 5.5 is cheaper: $8.00 against $20.00 per million tokens, blended at three input tokens per output token.
- Which is faster, Claude Opus 5.5 or GPT-6 Astra?
- GPT-6 Astra streams faster: 61 against 48 output tokens per second.
- Which has the larger context window?
- GPT-6 Astra accepts more context: 1.1M against 1M tokens.