Side-by-side technical and economic comparison between Google's Gemini 3.1 Pro Preview and Google's Gemini 2.5 Flash.
| Metric | Gemini 3.1 Pro Preview | Gemini 2.5 Flash | Advantage |
|---|---|---|---|
| Provider Organization | — | ||
| Standard Input / 1M | $2.00 | $0.30 | Gemini 2.5 Flash (85% lower) |
| Cached Input / 1M | $0.20 | $0.03 | Gemini 2.5 Flash lower |
| Output / 1M | $12.00 | $2.50 | Gemini 2.5 Flash lower |
| Context Window | 1.05M | 1.05M | Equal |
| Max Generation Tokens | 16.4k | 8.2k | Gemini 3.1 Pro Preview |
| Tokenizer Family | Google Gemini SentencePiece (256k vocabulary) | Google Gemma SentencePiece (~256k vocabulary) | — |
Opt for Gemini 3.1 Pro Preview when your engineering requirements prioritize Google's ecosystem, specific tokenizer efficiencies (Calibrated Gemini Tokenizer (±4%)), or when your expected prompt-to-completion ratios favor its $2/M input rate.
Opt for Gemini 2.5 Flash when looking for Google's tooling integration, specific context window depth (1.05M tokens), or when output generation volume favors its $2.5/M rate.