Claude Opus 5.5 vs GPT-5 Pro
Claude Opus 5.5 
GPT-5 Pro Verdict
- Claude Opus 5.5 (thinking) leads on quality: 70.7 vs 60.3.
- Claude Opus 5.5 (thinking) is stronger in composite, knowledge, long context, multimodal, reasoning.
- Claude Opus 5.5 (thinking) is 5.2× cheaper ($8.00 vs $41.25 per 1M blended).
| Metric | Claude Opus 5.5 (thinking) | GPT-5 Pro |
|---|---|---|
| BenchLeader Index | 70.7 | 60.3 |
| Composite score | 95.0 | – |
| Knowledge score | 85.0 | 66.9 |
| Long context score | 68.5 | – |
| Multimodal score | 71.9 | 67.4 |
| Reasoning score | 95.0 | 56.9 |
| Blended price $/M | $8.00 | $41.25 |
| Output speed | 48 tok/s | – |
| Time to first answer | 4.2 s | – |
| Context window | 1M | 400k |
| Humanity's Last Exam | – | 31.6% |
| SimpleBench | – | 61.6% |
| Epoch Capabilities Index | – | 150.3 |
| 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% | – |
| PRBench Finance | – | 51.1% |
| PRBench Legal | – | 49.9% |
| VISTA | – | 52.4% |
| MultiNRC | – | 65.2% |
| Kagi LLM Benchmark | – | 76.8% |
| ARC-AGI-1 | – | 70.2% |
| ARC-AGI-2 | – | 18.3% |
| CritPt | 31.7% | – |
| GDPval (AA) | 67.3% | – |
| FORTRESS | – | 15.2% |
| MASK | – | 86.0% |
| 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 | – |
| DeepSearchQA | – | 65.2% |
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 Pro: questions
- Is Claude Opus 5.5 better than GPT-5 Pro?
- Claude Opus 5.5 (thinking) leads on quality: 70.7 vs 60.3. 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 Pro?
- Claude Opus 5.5 is cheaper: $8.00 against $41.25 per million tokens, blended at three input tokens per output token.
- Which has the larger context window?
- Claude Opus 5.5 accepts more context: 1M against 400k tokens.