Gemini 3.1 Pro vs Gemini 3.5 Flash
Gemini 3.1 Pro Verdict
- Gemini 3.1 Pro and Gemini 3.5 Flash (medium) are level on quality (63.9 vs 63.9).
- Gemini 3.1 Pro is stronger in coding, long context, maths, reasoning.
- Gemini 3.5 Flash (medium) is stronger in agents & tools, composite, human preference, instruction following, knowledge, multimodal.
- Gemini 3.5 Flash (medium) is 1.3× cheaper ($3.38 vs $4.50 per 1M blended).
- Gemini 3.5 Flash (medium) streams 1.9× faster (209 vs 110 tokens per second).
| Metric | Gemini 3.1 Pro | Gemini 3.5 Flash (medium) |
|---|---|---|
| BenchLeader Index | 63.9 | 63.9 |
| Agents & tools score | 63.7 | 67.8 |
| Coding score | 59.8 | 58.9 |
| Composite score | 67.2 | 71.4 |
| Human preference score | 59.6 | 67.4 |
| Instruction following score | 69.5 | 72.2 |
| Knowledge score | 66.1 | 73.9 |
| Long context score | 67.6 | 63.6 |
| Maths score | 60.7 | – |
| Multimodal score | 66.1 | 67.6 |
| Reasoning score | 69.5 | 66.8 |
| Blended price $/M | $4.50 | $3.38 |
| Output speed | 110 tok/s | 209 tok/s |
| Time to first answer | 30.5 s | 17.0 s |
| Context window | 1.0M | 1M |
| GPQA Diamond | 94.1% | – |
| FrontierMath Tiers 1–3 | 59.6% | – |
| FrontierMath Tier 4 | 26.8% | – |
| OTIS Mock AIME | 95.6% | – |
| Humanity's Last Exam | 46.4% | – |
| Terminal-Bench | 80.2% | – |
| SimpleBench | 79.6% | – |
| SciCode | 58.9% | – |
| WeirdML | 72.1% | – |
| APEX-Agents | 33.5% | – |
| ProofBench | 26.0% | – |
| GSO-Bench | 22.6% | – |
| Epoch Capabilities Index | 155 | – |
| LMArena Text | 1487 | 1476 |
| LMArena Hard Prompts | 1507 | 1493 |
| LMArena Coding | 1521 | 1503 |
| LMArena WebDev | 1447 | 1491 |
| LMArena Vision | 1295 | 1306 |
| LMArena Agent | -5.3 | – |
| AA Intelligence Index | 30.4 | 33.6 |
| IFBench | 77.1% | 74.6% |
| AA-LCR | 82.0% | 74.3% |
| MMMU-Pro | 82.4% | 83.9% |
| AA-Omniscience | 31.9 | 20.8 |
| Terminal-Bench Hard | 53.8% | 39.4% |
| GPQA Diamond (AA) | 94.1% | 92.1% |
| Humanity's Last Exam (AA) | 47.0% | 41.3% |
| SciCode (AA) | 58.7% | – |
| τ²-Bench Telecom (AA) | 95.6% | 95.6% |
| AIME 2026 | 98.3% | – |
| HMMT February 2026 | 94.7% | – |
| MathArena Apex | 60.9% | – |
| MultiChallenge | 71.4% | – |
| PRBench Finance | 41.9% | – |
| PRBench Legal | 44.0% | – |
| MultiNRC | 64.7% | – |
| HiL-Bench | 35.3% | – |
| TutorBench | 53.0% | – |
| EQ-Bench 4 | 1142 | – |
| ARC-AGI-1 | 98.0% | – |
| ARC-AGI-2 | 77.1% | – |
| ARC-AGI-3 | 0.4% | – |
Data as of 2026-09-09. Best configuration of each model; every score links to its source on the model pages.