Gemini 3.8 Flash vs GPT-5 Pro
Gemini 3.8 Flash 
GPT-5 Pro Verdict
- Gemini 3.8 Flash (medium) leads on quality: 63.6 vs 60.8.
- Gemini 3.8 Flash (medium) is stronger in coding, composite, knowledge, long context, multimodal.
- GPT-5 Pro is stronger in reasoning.
- Gemini 3.8 Flash (medium) is 28× cheaper ($1.50 vs $41.25 per 1M blended).
| Metric | Gemini 3.8 Flash (medium) | GPT-5 Pro |
|---|---|---|
| BenchLeader Index | 63.6 | 60.8 |
| Coding score | 63.8 | – |
| Composite score | 79.6 | – |
| Knowledge score | 77.7 | 68.0 |
| Long context score | 68.6 | – |
| Multimodal score | 68.8 | 67.4 |
| Reasoning score | – | 57.6 |
| Blended price $/M | $1.50 | $41.25 |
| Output speed | 90 tok/s | – |
| Time to first answer | 11.7 s | – |
| Context window | 1M | 400k |
| Humanity's Last Exam | – | 31.6% |
| SimpleBench | – | 61.6% |
| SciCode | 54.4% | – |
| Epoch Capabilities Index | – | 150.3 |
| AA Intelligence Index | 40 | – |
| AA-LCR | 84.0% | – |
| MMMU-Pro | 84.2% | – |
| AA-Omniscience | 28.6 | – |
| GPQA Diamond (AA) | 93.5% | – |
| Humanity's Last Exam (AA) | 42.1% | – |
| SciCode (AA) | 55.1% | – |
| PRBench Finance | – | 51.1% |
| PRBench Legal | – | 49.9% |
| VISTA | – | 52.4% |
| MultiNRC | – | 65.2% |
| Kagi LLM Benchmark | – | 76.8% |
| ARC-AGI-1 | – | 70.2% |
| ARC-AGI-2 | – | 18.3% |
Data as of 2026-09-10. Best configuration of each model; every score links to its source on the model pages.
Gemini 3.8 Flash vs GPT-5 Pro: questions
- Is Gemini 3.8 Flash better than GPT-5 Pro?
- Gemini 3.8 Flash (medium) leads on quality: 63.6 vs 60.8. The BenchLeader Index combines every independent quality benchmark; Gemini 3.8 Flash (medium) is ahead overall as of 2026-09-10, but check the category scores for your use.
- Which is cheaper, Gemini 3.8 Flash or GPT-5 Pro?
- Gemini 3.8 Flash is cheaper: $1.50 against $41.25 per million tokens, blended at three input tokens per output token.
- Which has the larger context window?
- Gemini 3.8 Flash accepts more context: 1M against 400k tokens.