Claude Opus 5.5 vs Gemini 3.6 Flash
Claude Opus 5.5 
Gemini 3.6 Flash Verdict
- Claude Opus 5.5 (thinking) leads on quality: 70.7 vs 61.5.
- Claude Opus 5.5 (thinking) is stronger in composite, knowledge, long context, multimodal, reasoning.
- Gemini 3.6 Flash (high) is stronger in agents & tools, coding, human preference, maths.
- Gemini 3.6 Flash (high) is 5.3× cheaper ($1.50 vs $8.00 per 1M blended).
- Gemini 3.6 Flash (high) streams 3.9× faster (188 vs 48 tokens per second).
| Metric | Claude Opus 5.5 (thinking) | Gemini 3.6 Flash (high) |
|---|---|---|
| BenchLeader Index | 70.7 | 61.5 |
| Composite score | 95.0 | 58.8 |
| Knowledge score | 85.0 | 66.4 |
| Long context score | 68.5 | 66.1 |
| Multimodal score | 71.9 | 66.4 |
| Reasoning score | 95.0 | 64.2 |
| Agents & tools score | – | 53.6 |
| Coding score | – | 58.5 |
| Human preference score | – | 68.2 |
| Maths score | – | 61.3 |
| Blended price $/M | $8.00 | $1.50 |
| Output speed | 48 tok/s | 188 tok/s |
| Time to first answer | 4.2 s | 17.2 s |
| Context window | 1M | 1.0M |
| GPQA Diamond | – | 94.1% |
| FrontierMath Tiers 1–3 | – | 59.0% |
| FrontierMath Tier 4 | – | 21.9% |
| OTIS Mock AIME | – | 94.2% |
| SimpleQA Verified | – | 66.2% |
| SciCode | – | 52.7% |
| WeirdML | – | 56.1% |
| LMArena Text | – | 1480 |
| LMArena Hard Prompts | – | 1500 |
| LMArena Coding | – | 1517 |
| LMArena WebDev | – | 1537 |
| LMArena Vision | – | 1300 |
| LMArena Agent | – | -5.9 |
| LiveBench | – | 73.6% |
| LiveBench Reasoning | – | 85.2% |
| LiveBench Coding | – | 77.9% |
| LiveBench Agentic Coding | – | 43.4% |
| LiveBench Mathematics | – | 86.4% |
| LiveBench Data Analysis | – | 63.0% |
| LiveBench Language | – | 83.9% |
| LiveBench Instruction Following | – | 75.4% |
| AA Intelligence Index | 57.6 | 34.0 |
| AA-LCR | 84.7% | 80.0% |
| MMMU-Pro | 87.7% | 83.2% |
| AA-Omniscience | 46.4 | 22.1 |
| GPQA Diamond (AA) | – | 92.8% |
| Humanity's Last Exam (AA) | 61.4% | 40.8% |
| SciCode (AA) | 66.9% | 53.4% |
| LiveCodeBench | – | 88.1% |
| MMLU-Pro | – | 89.3% |
| IOI | – | 35.1% |
| LegalBench | – | 86.7% |
| CorpFin | – | 63.3% |
| TaxEval | – | 74.9% |
| Terminal-Bench 2.1 (Vals) | – | 73.8% |
| SWE-bench (Vals) | – | 79.6% |
| GPQA Diamond (Vals) | – | 93.4% |
| Vals Index | – | 55.4 |
| ARC-AGI-1 | – | 91.2% |
| ARC-AGI-2 | – | 60.4% |
| CritPt | 31.7% | 10.6% |
| GDPval (AA) | 67.3% | 38.2% |
| τ²-Bench Banking (AA) | – | 29.9% |
| BioMysteryBench | – | 58.5% |
| Code Migration | – | 30.9% |
| Excel Modeling Benchmark | – | 65.4% |
| Finance Agent v2 | – | 56.3% |
| Harvey's Legal Agent Benchmark | – | 3.3% |
| Legal Research Bench | – | 25.0% |
| MedCode | – | 53.1% |
| MedScribe | – | 79.7% |
| MMMU-Pro (Vals) | – | 88.4% |
| MortgageTax | – | 67.6% |
| ProgramBench | – | 0.0% |
| Public Benefits Bench | – | 56.6% |
| SAGE | – | 48.7% |
| Terminal-Bench 4.0 (Vals) | – | 4.5% |
| Terminal-Bench Science | – | 1.4% |
| Vals Multimodal Index | – | 65.1% |
| Vibe Code Bench v1.1 | – | 64.0% |
| LMArena Maths | – | 1504 |
| LMArena Creative Writing | – | 1470 |
| LMArena Instruction Following | – | 1473 |
| LMArena Multi-turn | – | 1485 |
| LMArena Longer Queries | – | 1487 |
| LMArena Document | – | 1453 |
| Chess Puzzles | – | 40.0% |
| Mystery Game Puzzles | – | 30.0% |
| DeepSWE | – | 46.7% |
| LMCA | – | 44.9% |
| DTBench | – | 95.5% |
| ALE-Bench | – | 715.5 |
| GDP.pdf | – | 14.0% |
| Terminal-Bench 4.0 (AA) | 59.6% | 7.1% |
| Terminal-Bench 2.1 (AA) | – | 77.5% |
| AutomationBench | 69.5% | – |
| GDP.pdf | 26.2% | – |
| Harvey LAB | 91.2% | – |
| AA-Omniscience: accuracy | 66.2% | 50.0% |
| AA-Omniscience: non-hallucination | 41.4% | 44.4% |
| 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 5.5 vs Gemini 3.6 Flash: questions
- Is Claude Opus 5.5 better than Gemini 3.6 Flash?
- Claude Opus 5.5 (thinking) leads on quality: 70.7 vs 61.5. 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 5.5 or Gemini 3.6 Flash?
- Gemini 3.6 Flash is cheaper: $1.50 against $8.00 per million tokens, blended at three input tokens per output token.
- Which is faster, Claude Opus 5.5 or Gemini 3.6 Flash?
- Gemini 3.6 Flash streams faster: 188 against 48 output tokens per second.
- Which has the larger context window?
- Gemini 3.6 Flash accepts more context: 1.0M against 1M tokens.