Gemini 2.5 Flash vs Gemini 3.1 Pro
Benchmarks, API pricing and specs, head to head. Data updated 2026-06-10.
Gemini 2.5 Flash
Google · Jun 2025
The 2025 fast-tier favorite: hybrid reasoning, full multimodality and a 1M context at $0.30/$2.50.
Gemini 3.1 Pro
Google · Mar 2026
Google's flagship with the industry's largest context window — 2M tokens — and frontier multimodal reasoning at $2/$12.
The verdict
Gemini 3.1 Pro wins 1 of the 1 benchmarks these models share, against 0 for Gemini 2.5 Flash. On price the gap is dramatic: Gemini 2.5 Flash works out roughly 5.3x cheaper per blended million tokens. Gemini 3.1 Pro also takes 2M of context versus 1.0M for Gemini 2.5 Flash.
Benchmark head-to-head 0–1
Specs & pricing
| Gemini 2.5 Flash | Gemini 3.1 Pro | |
|---|---|---|
| modhub Index | — | — |
| Input price / 1M | $0.3 | $2 |
| Output price / 1M | $2.5 | $12 |
| Context window | 1.0M | 2M |
| Max output | 66K | 66K |
| Open weights | no | no |
| Reasoning model | yes | yes |
| Multimodal input | text, image, audio, video | text, image, audio, video |
| Knowledge cutoff | Jan 2025 | Nov 2025 |
| Released | Jun 2025 | Mar 2026 |
| Example monthly cost* | $6.75 | $38.00 |
* 10M input + 1.5M output tokens per month at list prices, no caching. Green = better value on that row.
Frequently asked questions
- Which is better, Gemini 2.5 Flash or Gemini 3.1 Pro?
- Gemini 3.1 Pro wins 1 of the 1 benchmarks these models share, against 0 for Gemini 2.5 Flash. On price the gap is dramatic: Gemini 2.5 Flash works out roughly 5.3x cheaper per blended million tokens. Gemini 3.1 Pro also takes 2M of context versus 1.0M for Gemini 2.5 Flash.
- Which is cheaper, Gemini 2.5 Flash or Gemini 3.1 Pro?
- Gemini 2.5 Flash costs $0.3/$2.5 per million input/output tokens, while Gemini 3.1 Pro costs $2/$12. For a typical workload of 10M input and 1.5M output tokens per month, that's $6.75 versus $38.00.
- Which model is better for coding, Gemini 2.5 Flash or Gemini 3.1 Pro?
- On SWE-bench Verified — the standard agentic-coding benchmark — Gemini 3.1 Pro scores ~78% versus ~48.9% for Gemini 2.5 Flash, making Gemini 3.1 Pro the stronger pick for coding agents.
More comparisons
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