Claude Opus 4.1 vs GPT-5.5
Claude Opus 4.1 
GPT-5.5 Verdict
- GPT-5.5 leads on quality: 66.7 vs 58.2.
- Claude Opus 4.1 (thinking) is stronger in maths.
- GPT-5.5 is stronger in agents & tools, coding, composite, human preference, instruction following, knowledge, long context, multimodal, reasoning.
- GPT-5.5 is 2.7× cheaper ($11.25 vs $30.00 per 1M blended).
- GPT-5.5 streams 8.5× faster (85 vs 10 tokens per second).
| Metric | Claude Opus 4.1 (thinking) | GPT-5.5 |
|---|---|---|
| BenchLeader Index | 58.2 | 66.7 |
| Agents & tools score | 63.6 | 68.5 |
| Coding score | 53.3 | 57.2 |
| Composite score | 57.9 | 77.8 |
| Human preference score | 64.6 | 67.9 |
| Instruction following score | 52.6 | 73.6 |
| Knowledge score | 58.3 | 73.9 |
| Long context score | 64.5 | 68.8 |
| Maths score | 59.3 | – |
| Multimodal score | 56.5 | 64.9 |
| Reasoning score | 65.6 | 70.1 |
| Blended price $/M | $30.00 | $11.25 |
| Output speed | 10 tok/s | 85 tok/s |
| Time to first answer | 3.2 s | 58.6 s |
| Context window | 200k | 1.1M |
| Terminal-Bench | – | 84.7% |
| SimpleBench | – | 69.0% |
| Remote Labor Index | – | 6.3% |
| APEX-Agents | – | 38.5% |
| FrontierCode | – | 43.0% |
| Epoch Capabilities Index | – | 159.1 |
| LMArena Text | 1450 | 1477 |
| LMArena Hard Prompts | 1480 | 1498 |
| LMArena Coding | 1512 | 1509 |
| LMArena WebDev | – | 1458 |
| LMArena Vision | – | 1296 |
| LMArena Agent | – | 3 |
| AA Intelligence Index | 22.9 | 38.6 |
| IFBench | 55.4% | 75.8% |
| AA-LCR | 76.0% | 84.3% |
| MMMU-Pro | 67.9% | 79.9% |
| AA-Omniscience | – | 20.5 |
| Terminal-Bench Hard | 34.3% | 60.6% |
| GPQA Diamond (AA) | 80.9% | 93.5% |
| Humanity's Last Exam (AA) | 12.5% | 45.8% |
| SciCode (AA) | – | 55.8% |
| τ²-Bench Telecom (AA) | 71.4% | 93.9% |
| AIME (Vals) | 78.2% | – |
| LiveCodeBench | 66.5% | – |
| MMLU-Pro | 87.9% | – |
| TaxEval | 73.7% | – |
| MedQA | 93.6% | – |
| MGSM | 94.4% | – |
| GPQA Diamond (Vals) | 76.3% | – |
| MultiChallenge | 57.2% | – |
| VISTA | 48.4% | – |
| MultiNRC | 38.4% | – |
| HiL-Bench | – | 39.7% |
| TutorBench | 50.8% | – |
| EQ-Bench 4 | – | 1315 |
| Kagi LLM Benchmark | – | 88.8% |
Data as of 2026-09-10. Best configuration of each model; every score links to its source on the model pages.
Claude Opus 4.1 vs GPT-5.5: questions
- Is Claude Opus 4.1 better than GPT-5.5?
- GPT-5.5 leads on quality: 66.7 vs 58.2. The BenchLeader Index combines every independent quality benchmark; GPT-5.5 is ahead overall as of 2026-09-10, but check the category scores for your use.
- Is Claude Opus 4.1 better than GPT-5.5 for coding?
- GPT-5.5 scores higher in coding (57 vs 53 on the category index, where 50 is average).
- Is Claude Opus 4.1 better than GPT-5.5 for agentic tasks?
- GPT-5.5 scores higher in agentic tasks (69 vs 64 on the category index, where 50 is average).
- Which is cheaper, Claude Opus 4.1 or GPT-5.5?
- GPT-5.5 is cheaper: $11.25 against $30.00 per million tokens, blended at three input tokens per output token.
- Which is faster, Claude Opus 4.1 or GPT-5.5?
- GPT-5.5 streams faster: 85 against 10 output tokens per second.
- Which has the larger context window?
- GPT-5.5 accepts more context: 1.1M against 200k tokens.