Gemini 3.5 Flash vs GPT-5
Gemini 3.5 Flash 
GPT-5 Verdict
- Gemini 3.5 Flash (medium) leads on quality: 64.0 vs 60.8.
- Gemini 3.5 Flash (medium) is stronger in agents & tools, composite, human preference, instruction following, knowledge, multimodal, reasoning.
- GPT-5 is stronger in coding, long context, maths.
- They cost about the same ($3.38 per 1M blended).
- Gemini 3.5 Flash (medium) streams 2.7× faster (226 vs 85 tokens per second).
| Metric | Gemini 3.5 Flash (medium) | GPT-5 |
|---|---|---|
| BenchLeader Index | 64.0 | 60.8 |
| Agents & tools score | 68.0 | 51.0 |
| Coding score | 58.7 | 60.9 |
| Composite score | 71.6 | 58.1 |
| Human preference score | 67.5 | 61.7 |
| Instruction following score | 72.5 | 65.0 |
| Knowledge score | 74.2 | 62.2 |
| Long context score | 63.6 | 65.6 |
| Multimodal score | 67.6 | 59.6 |
| Reasoning score | 67.0 | 64.2 |
| Maths score | – | 72.8 |
| Blended price $/M | $3.38 | $3.44 |
| Output speed | 226 tok/s | 85 tok/s |
| Time to first answer | 12.0 s | 60.7 s |
| Context window | 1.0M | 400k |
| Terminal-Bench | – | 49.6% |
| SciCode | – | 42.9% |
| Remote Labor Index | – | 1.7% |
| WeirdML | – | 39.8% |
| APEX-Agents | – | 18.3% |
| Epoch Capabilities Index | – | 150 |
| LMArena Text | 1474 | 1427 |
| LMArena Hard Prompts | 1493 | 1449 |
| LMArena Coding | 1502 | 1462 |
| LMArena WebDev | 1492 | – |
| LMArena Vision | 1306 | 1232 |
| AA Intelligence Index | 33.6 | 23.0 |
| IFBench | 74.6% | 73.1% |
| AA-LCR | 74.3% | 78.2% |
| MMMU-Pro | 83.9% | 74.2% |
| AA-Omniscience | 20.8 | -8.7 |
| Terminal-Bench Hard | 39.4% | 32.6% |
| GPQA Diamond (AA) | 92.1% | 85.3% |
| Humanity's Last Exam (AA) | 41.3% | 28.5% |
| τ²-Bench Telecom (AA) | 95.6% | 84.8% |
| PRBench Finance | – | 51.3% |
| PRBench Legal | – | 49.0% |
| VISTA | – | 49.7% |
| MultiNRC | – | 52.1% |
| TutorBench | – | 55.3% |
| Kagi LLM Benchmark | – | 72.7% |
| IFEval (HELM) | – | 87.5% |
| Omni-MATH (HELM) | – | 64.7% |
| WildBench (HELM) | – | 85.7% |
| MMLU-Pro (HELM) | – | 86.3% |
| GPQA Diamond (HELM) | – | 79.1% |
| HELM Capabilities mean | – | 80.7% |
| Aider Polyglot | – | 88.0% |
| SWE-bench Verified (any scaffold) | – | 75.6% |
Data as of 2026-09-12. Best configuration of each model; every score links to its source on the model pages.
Gemini 3.5 Flash vs GPT-5: questions
- Is Gemini 3.5 Flash better than GPT-5?
- Gemini 3.5 Flash (medium) leads on quality: 64.0 vs 60.8. The BenchLeader Index combines every independent quality benchmark; Gemini 3.5 Flash (medium) is ahead overall as of 2026-09-12, but check the category scores for your use.
- Is Gemini 3.5 Flash better than GPT-5 for coding?
- GPT-5 scores higher in coding (61 vs 59 on the category index, where 50 is average).
- Is Gemini 3.5 Flash better than GPT-5 for agentic tasks?
- Gemini 3.5 Flash scores higher in agentic tasks (68 vs 51 on the category index, where 50 is average).
- Which is cheaper, Gemini 3.5 Flash or GPT-5?
- Gemini 3.5 Flash is cheaper: $3.38 against $3.44 per million tokens, blended at three input tokens per output token.
- Which is faster, Gemini 3.5 Flash or GPT-5?
- Gemini 3.5 Flash streams faster: 226 against 85 output tokens per second.
- Which has the larger context window?
- Gemini 3.5 Flash accepts more context: 1.0M against 400k tokens.