Claude Opus 4.5 vs Claude Opus 5.5
Claude Opus 4.5 Verdict
- Claude Opus 5.5 (thinking) leads on quality: 70.7 vs 60.6.
- Claude Opus 4.5 (thinking) is stronger in agents & tools, coding, instruction following, maths.
- Claude Opus 5.5 (thinking) is stronger in composite, knowledge, long context, multimodal, reasoning.
- Claude Opus 5.5 (thinking) is 1.3× cheaper ($8.00 vs $10.00 per 1M blended).
| Metric | Claude Opus 4.5 (thinking) | Claude Opus 5.5 (thinking) |
|---|---|---|
| BenchLeader Index | 60.6 | 70.7 |
| Agents & tools score | 74.5 | – |
| Coding score | 60.6 | – |
| Composite score | 64.7 | 95.0 |
| Instruction following score | 54.8 | – |
| Knowledge score | 60.6 | 85.0 |
| Long context score | 64.7 | 68.5 |
| Maths score | 64.0 | – |
| Multimodal score | 57.8 | 71.9 |
| Reasoning score | 55.7 | 95.0 |
| Blended price $/M | $10.00 | $8.00 |
| Output speed | 49 tok/s | 48 tok/s |
| Time to first answer | 16.5 s | 4.2 s |
| Context window | 200k | 1M |
| AA Intelligence Index | 29.1 | 57.6 |
| IFBench | 58.0% | – |
| AA-LCR | 77.3% | 84.7% |
| MMMU-Pro | 74.0% | 87.7% |
| AA-Omniscience | 14 | 46.4 |
| Terminal-Bench Hard | 47.0% | – |
| GPQA Diamond (AA) | 86.6% | – |
| Humanity's Last Exam (AA) | 30.1% | 61.4% |
| SciCode (AA) | – | 66.9% |
| 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% | – |
| ARC-AGI-2 | 37.6% | – |
| CritPt | 4.6% | 31.7% |
| GDPval (AA) | – | 67.3% |
| 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% | – |
| Terminal-Bench 4.0 (AA) | – | 59.6% |
| AutomationBench | – | 69.5% |
| GDP.pdf | – | 26.2% |
| Harvey LAB | – | 91.2% |
| AA-Omniscience: accuracy | 46.6% | 66.2% |
| AA-Omniscience: non-hallucination | 39.0% | 41.4% |
| AA-Briefcase | – | 1822 |
| DeepSearchQA | 24.0% | – |
Data as of 2026-09-22. Best configuration of each model; every score links to its source on the model pages.
Claude Opus 4.5 vs Claude Opus 5.5: questions
- Is Claude Opus 4.5 better than Claude Opus 5.5?
- Claude Opus 5.5 (thinking) leads on quality: 70.7 vs 60.6. 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 4.5 or Claude Opus 5.5?
- Claude Opus 5.5 is cheaper: $8.00 against $10.00 per million tokens, blended at three input tokens per output token.
- Which is faster, Claude Opus 4.5 or Claude Opus 5.5?
- Claude Opus 4.5 streams faster: 49 against 48 output tokens per second.
- Which has the larger context window?
- Claude Opus 5.5 accepts more context: 1M against 200k tokens.