Claude Opus 4.8 vs Claude Opus 5.5
Claude Opus 4.8 Verdict
- Claude Opus 5.5 (thinking) leads on quality: 70.7 vs 63.5.
- Claude Opus 4.8 (max) is stronger in agents & tools, coding, instruction following, maths.
- Claude Opus 5.5 (thinking) is stronger in composite, knowledge, long context, reasoning, multimodal.
- Claude Opus 5.5 (thinking) is 1.3× cheaper ($8.00 vs $10.00 per 1M blended).
| Metric | Claude Opus 4.8 (max) | Claude Opus 5.5 (thinking) |
|---|---|---|
| BenchLeader Index | 63.5 | 70.7 |
| Agents & tools score | 56.5 | – |
| Coding score | 61.5 | – |
| Composite score | 67.5 | 95.0 |
| Instruction following score | 62.0 | – |
| Knowledge score | 68.7 | 85.0 |
| Long context score | 64.9 | 68.5 |
| Maths score | 69.6 | – |
| Reasoning score | 71.3 | 95.0 |
| Multimodal score | – | 71.9 |
| Blended price $/M | $10.00 | $8.00 |
| Output speed | 57 tok/s | 48 tok/s |
| Time to first answer | 34.6 s | 4.2 s |
| Context window | 1M | 1M |
| GPQA Diamond | 91.0% | – |
| FrontierMath Tiers 1–3 | 80.0% | – |
| FrontierMath Tier 4 | 56.1% | – |
| OTIS Mock AIME | 98.3% | – |
| SimpleQA Verified | 53.0% | – |
| Terminal-Bench | 23.6% | – |
| OSWorld-Verified 2.0 | 20.6% | – |
| SciCode | 53.5% | – |
| APEX-Agents | 48.9% | – |
| ProofBench | 69.0% | – |
| LiveBench | 76.2% | – |
| LiveBench Reasoning | 89.2% | – |
| LiveBench Coding | 81.8% | – |
| LiveBench Agentic Coding | 50.5% | – |
| LiveBench Mathematics | 94.3% | – |
| LiveBench Data Analysis | 66.0% | – |
| LiveBench Language | 79.7% | – |
| LiveBench Instruction Following | 72.0% | – |
| AA Intelligence Index | 41.8 | 57.6 |
| IFBench | 62.2% | – |
| AA-LCR | 77.7% | 84.7% |
| MMMU-Pro | – | 87.7% |
| AA-Omniscience | 28.8 | 46.4 |
| Terminal-Bench Hard | 58.3% | – |
| GPQA Diamond (AA) | 92.0% | – |
| Humanity's Last Exam (AA) | 48.7% | 61.4% |
| SciCode (AA) | 54.4% | 66.9% |
| τ²-Bench Telecom (AA) | 94.4% | – |
| AIME 2026 | 100.0% | – |
| HMMT February 2026 | 95.5% | – |
| MathArena Apex | 81.3% | – |
| MCP Atlas | 82.2% | – |
| ARC-AGI-1 | 92.5% | – |
| CritPt | 20.9% | 31.7% |
| GDPval (AA) | 46.9% | 67.3% |
| τ²-Bench Banking (AA) | 34.2% | – |
| Analyst Agent (AA) | 45.0% | – |
| DrugDiscoveryBench | 46.8% | – |
| FORTRESS | 18.2% | – |
| Chess Puzzles | 34.0% | – |
| EBR-bench | 28.6% | – |
| Mystery Game Puzzles | 36.0% | – |
| PostTrainBench | 32.9% | – |
| DeepSWE | 59.0% | – |
| LMCA | 57.5% | – |
| DTBench | 94.9% | – |
| Vending-Bench 2 | 2992.3 | – |
| GDP.pdf | 24.0% | – |
| Terminal-Bench 4.0 (AA) | 21.7% | 59.6% |
| Terminal-Bench 2.1 (AA) | 84.6% | – |
| AutomationBench | – | 69.5% |
| GDP.pdf | – | 26.2% |
| Harvey LAB | – | 91.2% |
| AA-Omniscience: accuracy | 48.8% | 66.2% |
| AA-Omniscience: non-hallucination | 60.8% | 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 4.8 vs Claude Opus 5.5: questions
- Is Claude Opus 4.8 better than Claude Opus 5.5?
- Claude Opus 5.5 (thinking) leads on quality: 70.7 vs 63.5. 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 4.8 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 4.8 or Claude Opus 5.5?
- Claude Opus 4.8 streams faster: 57 against 48 output tokens per second.
- Which has the larger context window?
- Both accept 1M tokens of context.