Claude Opus 5.5 vs GPT-5.5 Pro
Claude Opus 5.5 
GPT-5.5 Pro Verdict
- Claude Opus 5.5 (thinking) leads on quality: 70.7 vs 67.0.
- Claude Opus 5.5 (thinking) is stronger in composite, knowledge, long context, multimodal, reasoning.
- GPT-5.5 Pro (xhigh) is stronger in maths.
- Claude Opus 5.5 (thinking) is 8.4× cheaper ($8.00 vs $67.50 per 1M blended).
- Claude Opus 5.5 (thinking) streams 12.0× faster (48 vs 4 tokens per second).
| Metric | Claude Opus 5.5 (thinking) | GPT-5.5 Pro (xhigh) |
|---|---|---|
| BenchLeader Index | 70.7 | 67.0 |
| Composite score | 95.0 | – |
| Knowledge score | 85.0 | – |
| Long context score | 68.5 | – |
| Multimodal score | 71.9 | – |
| Reasoning score | 95.0 | 80.1 |
| Maths score | – | 74.3 |
| Blended price $/M | $8.00 | $67.50 |
| Output speed | 48 tok/s | 4 tok/s |
| Time to first answer | 4.2 s | 3.5 s |
| Context window | 1M | 1.1M |
| FrontierMath Tiers 1–3 | – | 87.7% |
| FrontierMath Tier 4 | – | 78.0% |
| AA Intelligence Index | 57.6 | – |
| AA-LCR | 84.7% | – |
| MMMU-Pro | 87.7% | – |
| AA-Omniscience | 46.4 | – |
| Humanity's Last Exam (AA) | 61.4% | – |
| SciCode (AA) | 66.9% | – |
| ARC-AGI-1 | – | 95.0% |
| ARC-AGI-2 | – | 84.2% |
| CritPt | 31.7% | 30.6% |
| GDPval (AA) | 67.3% | – |
| LMCA | – | 53.9% |
| DTBench | – | 96.0% |
| Terminal-Bench 4.0 (AA) | 59.6% | – |
| AutomationBench | 69.5% | – |
| GDP.pdf | 26.2% | – |
| Harvey LAB | 91.2% | – |
| AA-Omniscience: accuracy | 66.2% | – |
| AA-Omniscience: non-hallucination | 41.4% | – |
| AA-Briefcase | 1822 | – |
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-5.5 Pro: questions
- Is Claude Opus 5.5 better than GPT-5.5 Pro?
- Claude Opus 5.5 (thinking) leads on quality: 70.7 vs 67.0. The BenchLeader Index combines every independent quality benchmark; Claude Opus 5.5 (thinking) 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-5.5 Pro?
- Claude Opus 5.5 is cheaper: $8.00 against $67.50 per million tokens, blended at three input tokens per output token.
- Which is faster, Claude Opus 5.5 or GPT-5.5 Pro?
- Claude Opus 5.5 streams faster: 48 against 4 output tokens per second.
- Which has the larger context window?
- GPT-5.5 Pro accepts more context: 1.1M against 1M tokens.