Gemini 3 Flash vs GPT-5.5 Pro
Gemini 3 Flash 
GPT-5.5 Pro Verdict
- GPT-5.5 Pro (xhigh) leads on quality: 67.1 vs 60.4.
- Gemini 3 Flash (thinking) is stronger in agents & tools, composite, instruction following, knowledge, long context, multimodal.
- GPT-5.5 Pro (xhigh) is stronger in reasoning, maths.
- Gemini 3 Flash (thinking) is 60× cheaper ($1.13 vs $67.50 per 1M blended).
- Gemini 3 Flash (thinking) streams 51.2× faster (205 vs 4 tokens per second).
| Metric | Gemini 3 Flash (thinking) | GPT-5.5 Pro (xhigh) |
|---|---|---|
| BenchLeader Index | 60.4 | 67.1 |
| Agents & tools score | 55.1 | – |
| Composite score | 62.3 | – |
| Instruction following score | 75.6 | – |
| Knowledge score | 69.0 | – |
| Long context score | 65.4 | – |
| Multimodal score | 64.5 | – |
| Reasoning score | 58.5 | 80.1 |
| Maths score | – | 74.5 |
| Blended price $/M | $1.13 | $67.50 |
| Output speed | 205 tok/s | 4 tok/s |
| Time to first answer | 6.0 s | 3.5 s |
| Context window | 1.0M | 1.1M |
| FrontierMath Tiers 1–3 | – | 87.7% |
| FrontierMath Tier 4 | – | 78.0% |
| AA Intelligence Index | 26.3 | – |
| IFBench | 78.0% | – |
| AA-LCR | 78.0% | – |
| MMMU-Pro | 79.9% | – |
| AA-Omniscience | 10.1 | – |
| Terminal-Bench Hard | 38.6% | – |
| GPQA Diamond (AA) | 89.8% | – |
| Humanity's Last Exam (AA) | 36.6% | – |
| τ²-Bench Telecom (AA) | 80.4% | – |
| ARC-AGI-1 | – | 95.0% |
| ARC-AGI-2 | – | 84.2% |
| CritPt | 8.6% | 30.6% |
| τ²-Bench Banking (AA) | 20.8% | – |
| APEX-Agents (AA) | 27.7% | – |
| LMCA | – | 53.9% |
| DTBench | – | 96.0% |
Data as of 2026-09-19. Best configuration of each model; every score links to its source on the model pages.
Gemini 3 Flash vs GPT-5.5 Pro: questions
- Is Gemini 3 Flash better than GPT-5.5 Pro?
- GPT-5.5 Pro (xhigh) leads on quality: 67.1 vs 60.4. The BenchLeader Index combines every independent quality benchmark; GPT-5.5 Pro (xhigh) is ahead overall as of 2026-09-19, but check the category scores for your use.
- Which is cheaper, Gemini 3 Flash or GPT-5.5 Pro?
- Gemini 3 Flash is cheaper: $1.13 against $67.50 per million tokens, blended at three input tokens per output token.
- Which is faster, Gemini 3 Flash or GPT-5.5 Pro?
- Gemini 3 Flash streams faster: 205 against 4 output tokens per second.
- Which has the larger context window?
- GPT-5.5 Pro accepts more context: 1.1M against 1.0M tokens.