Claude Opus 4.5 vs GPT-5.5 Pro
Claude Opus 4.5 
GPT-5.5 Pro Verdict
- GPT-5.5 Pro (xhigh) leads on quality: 67.1 vs 60.8.
- Claude Opus 4.5 (thinking) is stronger in agents & tools, coding, composite, instruction following, knowledge, long context, multimodal.
- GPT-5.5 Pro (xhigh) is stronger in maths, reasoning.
- Claude Opus 4.5 (thinking) is 6.8× cheaper ($10.00 vs $67.50 per 1M blended).
- Claude Opus 4.5 (thinking) streams 11.8× faster (47 vs 4 tokens per second).
| Metric | Claude Opus 4.5 (thinking) | GPT-5.5 Pro (xhigh) |
|---|---|---|
| BenchLeader Index | 60.8 | 67.1 |
| Agents & tools score | 74.5 | – |
| Coding score | 60.5 | – |
| Composite score | 65.9 | – |
| Instruction following score | 54.8 | – |
| Knowledge score | 60.8 | – |
| Long context score | 65.1 | – |
| Maths score | 64.0 | 74.5 |
| Multimodal score | 58.0 | – |
| Reasoning score | 56.0 | 80.1 |
| Blended price $/M | $10.00 | $67.50 |
| Output speed | 47 tok/s | 4 tok/s |
| Time to first answer | 15.5 s | 3.5 s |
| Context window | 200k | 1.1M |
| FrontierMath Tiers 1–3 | – | 87.7% |
| FrontierMath Tier 4 | – | 78.0% |
| AA Intelligence Index | 29.1 | – |
| IFBench | 58.0% | – |
| AA-LCR | 77.3% | – |
| MMMU-Pro | 74.0% | – |
| AA-Omniscience | 14 | – |
| Terminal-Bench Hard | 47.0% | – |
| GPQA Diamond (AA) | 86.6% | – |
| Humanity's Last Exam (AA) | 30.1% | – |
| τ²-Bench Telecom (AA) | 89.5% | – |
| AIME (Vals) | 95.4% | – |
| LiveCodeBench | 83.7% | – |
| MMLU-Pro | 87.3% | – |
| LegalBench | 84.6% | – |
| CorpFin | 65.1% | – |
| TaxEval | 74.9% | – |
| MedQA | 95.9% | – |
| MGSM | 95.2% | – |
| SWE-bench (Vals) | 76.4% | – |
| GPQA Diamond (Vals) | 85.9% | – |
| MultiChallenge | 59.0% | – |
| PRBench Finance | 46.2% | – |
| PRBench Legal | 44.2% | – |
| VISTA | 46.4% | – |
| MultiNRC | 48.6% | – |
| TutorBench | 51.2% | – |
| Kagi LLM Benchmark | 80.2% | – |
| ARC-AGI-1 | 80.0% | 95.0% |
| ARC-AGI-2 | 37.6% | 84.2% |
| CritPt | 4.6% | 30.6% |
| CaseLaw v2 | 62.6% | – |
| MedCode | 49.2% | – |
| MedScribe | 85.3% | – |
| MMMU-Pro (Vals) | 83.0% | – |
| MortgageTax | 67.7% | – |
| SAGE | 52.1% | – |
| Terminal-Bench 2.0 (Vals) | 53.9% | – |
| Vibe Code Bench v1.1 | 20.6% | – |
| FORTRESS | 9.6% | – |
| MASK | 92.5% | – |
| LMCA | – | 53.9% |
| DTBench | – | 96.0% |
Data as of 2026-09-19. Best configuration of each model; every score links to its source on the model pages.
Claude Opus 4.5 vs GPT-5.5 Pro: questions
- Is Claude Opus 4.5 better than GPT-5.5 Pro?
- GPT-5.5 Pro (xhigh) leads on quality: 67.1 vs 60.8. The BenchLeader Index combines every independent quality benchmark; GPT-5.5 Pro (xhigh) is ahead overall as of 2026-09-19, but check the category scores for your use.
- Which is cheaper, Claude Opus 4.5 or GPT-5.5 Pro?
- Claude Opus 4.5 is cheaper: $10.00 against $67.50 per million tokens, blended at three input tokens per output token.
- Which is faster, Claude Opus 4.5 or GPT-5.5 Pro?
- Claude Opus 4.5 streams faster: 47 against 4 output tokens per second.
- Which has the larger context window?
- GPT-5.5 Pro accepts more context: 1.1M against 200k tokens.