Gemini 3.5 Flash vs GPT-5.1-Instant
Both have similar output pricing, while Gemini 3.5 Flash offers a larger context window. Choose Gemini 3.5 Flash or GPT-5.1-Instant based on the trade-off between cost, context, and the benchmarks that matter for your use case.
| Spec | Gemini 3.5 Flash | GPT-5.1-Instant |
|---|---|---|
| Provider | Poe | |
| Input / 1M tokens | $1.50 | $1.10 |
| Output / 1M tokens | $9.00 | $9.00 |
| Context window | 1M | 128K |
| Parameters | — | — |
| Open weights | No | No |
| Released | May 2026 | Nov 2025 |
| LiveBench score | 75.8 | — |
| LMArena (Chatbot Arena) Elo score | 1482 | — |
| LMArena WebDev Elo score | 1499 | — |
| Epoch Capabilities Index score | 155 | — |
| LMArena Vision Elo score | 1308 | — |
| GPQA Diamond score | 92.8 | — |
| FrontierMath score | 39.0 | — |
FAQ
Is Gemini 3.5 Flash or GPT-5.1-Instant cheaper?
Gemini 3.5 Flash and GPT-5.1-Instant have comparable output pricing.
Which has the larger context window, Gemini 3.5 Flash or GPT-5.1-Instant?
Gemini 3.5 Flash has the larger context window (1M tokens).
Pricing is indicative — confirm with the provider before production use. Highlighted values indicate the better figure for that row.