Claude Opus 4.5 vs Gemini 3 Flash
Claude Opus 4.5 
Gemini 3 Flash Verdict
- Claude Opus 4.5 (thinking) and Gemini 3 Flash (thinking) are level on quality (60.7 vs 61.6).
- Claude Opus 4.5 (thinking) is stronger in agents & tools, coding, composite, maths, reasoning.
- Gemini 3 Flash (thinking) is stronger in instruction following, knowledge, long context, multimodal.
- Gemini 3 Flash (thinking) is 8.9× cheaper ($1.13 vs $10.00 per 1M blended).
- Gemini 3 Flash (thinking) streams 4.0× faster (180 vs 45 tokens per second).
| Metric | Claude Opus 4.5 (thinking) | Gemini 3 Flash (thinking) |
|---|---|---|
| BenchLeader Index | 60.7 | 61.6 |
| Agents & tools score | 74.6 | 67.4 |
| Coding score | 56.4 | – |
| Composite score | 65.8 | 62.3 |
| Instruction following score | 54.8 | 75.4 |
| Knowledge score | 61.0 | 69.0 |
| Long context score | 65.2 | 65.5 |
| Maths score | 64.0 | – |
| Multimodal score | 58.0 | 64.4 |
| Reasoning score | 58.6 | – |
| Blended price $/M | $10.00 | $1.13 |
| Output speed | 45 tok/s | 180 tok/s |
| Time to first answer | 17.3 s | 6.1 s |
| Context window | 200k | 1M |
| AA Intelligence Index | 29.1 | 26.3 |
| IFBench | 58.0% | 78.0% |
| AA-LCR | 77.3% | 78.0% |
| MMMU-Pro | 74.0% | 79.9% |
| AA-Omniscience | 14 | 10.1 |
| Terminal-Bench Hard | 47.0% | 38.6% |
| GPQA Diamond (AA) | 86.6% | 89.8% |
| Humanity's Last Exam (AA) | 30.1% | 36.6% |
| τ²-Bench Telecom (AA) | 89.5% | 80.4% |
| 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 Flash: questions
- Is Claude Opus 4.5 better than Gemini 3 Flash?
- Claude Opus 4.5 (thinking) and Gemini 3 Flash (thinking) are level on quality (60.7 vs 61.6). The BenchLeader Index combines every independent quality benchmark; Gemini 3 Flash (thinking) 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 Flash for agentic tasks?
- Claude Opus 4.5 scores higher in agentic tasks (75 vs 67 on the category index, where 50 is average).
- Which is cheaper, Claude Opus 4.5 or Gemini 3 Flash?
- Gemini 3 Flash is cheaper: $1.13 against $10.00 per million tokens, blended at three input tokens per output token.
- Which is faster, Claude Opus 4.5 or Gemini 3 Flash?
- Gemini 3 Flash streams faster: 180 against 45 output tokens per second.
- Which has the larger context window?
- Gemini 3 Flash accepts more context: 1M against 200k tokens.