Gemini 2.5 Pro vs Gemini 3.1 Pro
Benchmarks, API pricing and specs, head to head. Data updated 2026-06-10.
Gemini 2.5 Pro
70.9Google · Mar 2025
Google's 2025 workhorse flagship — first mainstream thinking model with a 1M context, still widely deployed.
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 Pro. Gemini 2.5 Pro is about 1.3x cheaper per blended million tokens (3:1 input:output mix). Gemini 3.1 Pro also takes 2M of context versus 1.0M for Gemini 2.5 Pro.
Benchmark head-to-head 0–1
Specs & pricing
| Gemini 2.5 Pro | Gemini 3.1 Pro | |
|---|---|---|
| modhub Index | 70.9 | — |
| Input price / 1M | $1.25 | $2 |
| Output price / 1M | $10 | $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 | Mar 2025 | Mar 2026 |
| Example monthly cost* | $27.50 | $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 Pro or Gemini 3.1 Pro?
- Gemini 3.1 Pro wins 1 of the 1 benchmarks these models share, against 0 for Gemini 2.5 Pro. Gemini 2.5 Pro is about 1.3x cheaper per blended million tokens (3:1 input:output mix). Gemini 3.1 Pro also takes 2M of context versus 1.0M for Gemini 2.5 Pro.
- Which is cheaper, Gemini 2.5 Pro or Gemini 3.1 Pro?
- Gemini 2.5 Pro costs $1.25/$10 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 $27.50 versus $38.00.
- Which model is better for coding, Gemini 2.5 Pro or Gemini 3.1 Pro?
- On SWE-bench Verified — the standard agentic-coding benchmark — Gemini 3.1 Pro scores ~78% versus 63.8% for Gemini 2.5 Pro, making Gemini 3.1 Pro the stronger pick for coding agents.
More comparisons
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