Gemini 3.1 Pro vs Gemini 2.5 Flash
A direct API-pricing comparison between Gemini 3.1 Pro and Gemini 2.5 Flash. Below: every cost dimension side by side, then the bottom line for a typical workload.
Bottom line
For a typical 5K-in / 1K-out request, Gemini 2.5 Flash is the cheaper choice at $0.0040 per call — 5.5× less than Gemini 3.1 Pro at $0.022.
| Gemini 3.1 ProGoogle | Gemini 2.5 FlashGoogle | |
|---|---|---|
| Input / 1M tokens | $2.00 | $0.300 |
| Output / 1M tokens | $12.00 | $2.50 |
| Cached input / 1M | — | $0.075 |
| Context window | 1M | 1M |
| Provider |
Green = cheaper on that line. Prices are estimates from public pricing pages; verify against Google and Google before relying on them.
Which is cheaper, Gemini 3.1 Pro or Gemini 2.5 Flash?
On output tokens — usually the dominant cost — Gemini 3.1 Pro charges $12.00 per million versus $2.50 for Gemini 2.5 Flash. The right pick depends on your input/output ratio and how much you can serve from cache. Use the calculator to model your exact traffic.