Claude Opus 4.5 vs Gemini 3.5 Flash
Claude Opus 4.5 
Gemini 3.5 Flash Verdict
- Gemini 3.5 Flash (medium) leads on quality: 64.1 vs 60.7.
- Claude Opus 4.5 (thinking) is stronger in agents & tools, long context, maths.
- Gemini 3.5 Flash (medium) is stronger in coding, composite, instruction following, knowledge, multimodal, reasoning, human preference.
- Gemini 3.5 Flash (medium) is 3.0× cheaper ($3.38 vs $10.00 per 1M blended).
- Gemini 3.5 Flash (medium) streams 4.9× faster (217 vs 45 tokens per second).
| Metric | Claude Opus 4.5 (thinking) | Gemini 3.5 Flash (medium) |
|---|---|---|
| BenchLeader Index | 60.7 | 64.1 |
| Agents & tools score | 74.6 | 68.0 |
| Coding score | 56.4 | 58.9 |
| Composite score | 65.8 | 71.5 |
| Instruction following score | 54.8 | 72.5 |
| Knowledge score | 61.0 | 74.0 |
| Long context score | 65.2 | 63.6 |
| Maths score | 64.0 | – |
| Multimodal score | 58.0 | 67.6 |
| Reasoning score | 58.6 | 67.1 |
| Human preference score | – | 67.8 |
| Blended price $/M | $10.00 | $3.38 |
| Output speed | 45 tok/s | 217 tok/s |
| Time to first answer | 17.3 s | 15.5 s |
| Context window | 200k | 1M |
| LMArena Text | – | 1476 |
| LMArena Hard Prompts | – | 1493 |
| LMArena Coding | – | 1503 |
| LMArena WebDev | – | 1491 |
| LMArena Vision | – | 1306 |
| AA Intelligence Index | 29.1 | 33.6 |
| IFBench | 58.0% | 74.6% |
| AA-LCR | 77.3% | 74.3% |
| MMMU-Pro | 74.0% | 83.9% |
| AA-Omniscience | 14 | 20.8 |
| Terminal-Bench Hard | 47.0% | 39.4% |
| GPQA Diamond (AA) | 86.6% | 92.1% |
| Humanity's Last Exam (AA) | 30.1% | 41.3% |
| τ²-Bench Telecom (AA) | 89.5% | 95.6% |
| AIME (Vals) | 95.4% | – |
| LiveCodeBench | 83.7% | – |
| MMLU-Pro | 87.3% | – |
| IOI | 20.3% | – |
| 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% | – |
Data as of 2026-09-10. Best configuration of each model; every score links to its source on the model pages.
Claude Opus 4.5 vs Gemini 3.5 Flash: questions
- Is Claude Opus 4.5 better than Gemini 3.5 Flash?
- Gemini 3.5 Flash (medium) leads on quality: 64.1 vs 60.7. The BenchLeader Index combines every independent quality benchmark; Gemini 3.5 Flash (medium) is ahead overall as of 2026-09-10, but check the category scores for your use.
- Is Claude Opus 4.5 better than Gemini 3.5 Flash for coding?
- Gemini 3.5 Flash scores higher in coding (59 vs 56 on the category index, where 50 is average).
- Is Claude Opus 4.5 better than Gemini 3.5 Flash for agentic tasks?
- Claude Opus 4.5 scores higher in agentic tasks (75 vs 68 on the category index, where 50 is average).
- Which is cheaper, Claude Opus 4.5 or Gemini 3.5 Flash?
- Gemini 3.5 Flash is cheaper: $3.38 against $10.00 per million tokens, blended at three input tokens per output token.
- Which is faster, Claude Opus 4.5 or Gemini 3.5 Flash?
- Gemini 3.5 Flash streams faster: 217 against 45 output tokens per second.
- Which has the larger context window?
- Gemini 3.5 Flash accepts more context: 1M against 200k tokens.