Claude Sonnet 4.5 vs GPT-6 Astra
Claude Sonnet 4.5 
GPT-6 Astra Verdict
- GPT-6 Astra (max) leads on quality: 70.5 vs 57.9.
- GPT-6 Astra (max) is stronger in coding, human preference, reasoning, agents & tools, composite, knowledge, maths.
- Claude Sonnet 4.5 (high) is 3.3× cheaper ($6.00 vs $20.00 per 1M blended).
- GPT-6 Astra (max) streams 1.5× faster (60 vs 40 tokens per second).
| Metric | Claude Sonnet 4.5 (high) | GPT-6 Astra (max) |
|---|---|---|
| BenchLeader Index | 57.9 | 70.5 |
| Coding score | 56.4 | 77.3 |
| Human preference score | 65.3 | 67.9 |
| Reasoning score | 66.4 | 72.7 |
| Agents & tools score | – | 68.2 |
| Composite score | – | 72.9 |
| Knowledge score | – | 80.0 |
| Maths score | – | 77.2 |
| Blended price $/M | $6.00 | $20.00 |
| Output speed | 40 tok/s | 60 tok/s |
| Time to first answer | 1.2 s | 321.0 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% |
| FrontierCode | – | 53.3% |
| LMArena Text | 1456 | 1478 |
| LMArena Hard Prompts | 1487 | 1495 |
| LMArena Coding | 1520 | 1537 |
| LMArena WebDev | 1393 | 1800 |
| LMArena Agent | – | 12.4 |
| 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% |
| IOI | – | 100.0% |
| Terminal-Bench 2.1 (Vals) | – | 87.3% |
| Vals Index | – | 66.6 |
| SWE-bench Verified (bash only) | 71.4% | – |
| ARC-AGI-1 | – | 97.5% |
| ARC-AGI-2 | – | 95.0% |
| ARC-AGI-3 | – | 98.6% |
Data as of 2026-09-13. Best configuration of each model; every score links to its source on the model pages.
Claude Sonnet 4.5 vs GPT-6 Astra: questions
- Is Claude Sonnet 4.5 better than GPT-6 Astra?
- GPT-6 Astra (max) leads on quality: 70.5 vs 57.9. The BenchLeader Index combines every independent quality benchmark; GPT-6 Astra (max) is ahead overall as of 2026-09-13, but check the category scores for your use.
- Is Claude Sonnet 4.5 better than GPT-6 Astra for coding?
- GPT-6 Astra scores higher in coding (77 vs 56 on the category index, where 50 is average).
- Which is cheaper, Claude Sonnet 4.5 or GPT-6 Astra?
- Claude Sonnet 4.5 is cheaper: $6.00 against $20.00 per million tokens, blended at three input tokens per output token.
- Which is faster, Claude Sonnet 4.5 or GPT-6 Astra?
- GPT-6 Astra streams faster: 60 against 40 output tokens per second.
- Which has the larger context window?
- GPT-6 Astra accepts more context: 1.1M against 1M tokens.