Model comparison - Same provider, successor
Gemini 2.5 Pro vs Gemini 3.1 Pro Preview
Gemini 2.5 Pro and Gemini 3.1 Pro Preview are both Google models. On list price, Gemini 3.1 Pro Preview charges 1.6x Gemini 2.5 Pro's input price ($2 vs $1.25 per 1M tokens), and Gemini 2.5 Pro charges 17% less than Gemini 3.1 Pro Preview for output ($10 vs $12 per 1M tokens). Gemini 2.5 Pro and Gemini 3.1 Pro Preview both have a 1,048,576-token context window, and both return up to 65,536 output tokens per response. Gemini 2.5 Pro was released on June 17, 2025 and Gemini 3.1 Pro Preview on February 19, 2026. Both are closed-weights models, available only through an API.
Last verified from each provider's pricing page. All sources
Side-by-side specs
| Spec | Gemini 2.5 Pro | Gemini 3.1 Pro Preview |
|---|---|---|
| Provider | ||
| Input / 1M tokens | $1.25 | $2 |
| Output / 1M tokens | $10 | $12 |
| Cache read / 1M | $0.125 | $0.20 |
| Batch input / 1M | $0.625 | $1 |
| Batch output / 1M | $5 | $6 |
| Long-context rates above | 200,000 tokens | 200,000 tokens |
| Context window | 1,048,576 | 1,048,576 |
| Max output | 65,536 | 65,536 |
| Release date | ||
| Weights | Closed | Closed |
| API model id | gemini-2.5-pro | gemini-3.1-pro-preview |
| AI Gateway id | google/gemini-2.5-pro | google/gemini-3.1-pro-preview |
| Last verified |
Prices in USD per 1M tokens at each provider's standard first-party rate. A dash means the provider does not bill that item separately or no primary page states it.
What each costs in practice
The same three workloads every model page uses, worked from each model's standard list rates. Swap in your own token counts with the math on each model's page.
| Workload | Gemini 2.5 Pro | Gemini 3.1 Pro Preview |
|---|---|---|
| One agent session1M input tokens and 100K output tokens, no caching. | $2.25 | $3.20 |
| A chat app10,000 requests a day at 2K input and 500 output tokens each. | $75.00$2,250.00 per 30-day month | $100.00$3,000.00 per 30-day month |
| The same session at a 90% cache hit90% of the input is read from the prompt cache. The one-time cache write premium is not included. | $1.24 | $1.58 |
Show the math
Gemini 2.5 Pro
- One agent sessionInput: 1M x $1.25 = $1.25Output: 0.1M x $10 = $1.00
- A chat appInput: 20M x $1.25 = $25.00Output: 5M x $10 = $50.00
- The same session at a 90% cache hitCached input: 0.9M x $0.125 = $0.1125Uncached input: 0.1M x $1.25 = $0.125Output: 0.1M x $10 = $1.00
Gemini 3.1 Pro Preview
- One agent sessionInput: 1M x $2 = $2.00Output: 0.1M x $12 = $1.20
- A chat appInput: 20M x $2 = $40.00Output: 5M x $12 = $60.00
- The same session at a 90% cache hitCached input: 0.9M x $0.20 = $0.18Uncached input: 0.1M x $2 = $0.20Output: 0.1M x $12 = $1.20
Benchmarks under the same setting
No board in the benchmark directory lists both Gemini 2.5 Pro and Gemini 3.1 Pro Preview under the same setting, so there is no like-for-like score to show here.
Set them up in your tools
Step-by-step guides whose official docs list Gemini 2.5 Pro or Gemini 3.1 Pro Preview by model id.
- Use Gemini in ClineLists Gemini 3.1 Pro Preview and Gemini 2.5 Pro
- Use Gemini in ContinueLists Gemini 3.1 Pro Preview and Gemini 2.5 Pro
- Use Gemini in CursorLists Gemini 3.1 Pro Preview and Gemini 2.5 Pro
- Use Gemini in GooseLists Gemini 3.1 Pro Preview and Gemini 2.5 Pro
- Use Gemini in Kilo CodeLists Gemini 3.1 Pro Preview and Gemini 2.5 Pro
- Use Gemini in OpenCodeLists Gemini 3.1 Pro Preview and Gemini 2.5 Pro
- Use Gemini in ZedLists Gemini 3.1 Pro Preview and Gemini 2.5 Pro
Model pages
FAQ
How do Gemini 2.5 Pro and Gemini 3.1 Pro Preview compare on price?
On list price, Gemini 3.1 Pro Preview charges 1.6x Gemini 2.5 Pro's input price ($2 vs $1.25 per 1M tokens), and Gemini 2.5 Pro charges 17% less than Gemini 3.1 Pro Preview for output ($10 vs $12 per 1M tokens). For one agent session of 1M input and 100K output tokens with no caching, that is $2.25 on Gemini 2.5 Pro and $3.20 on Gemini 3.1 Pro Preview. Prices are each provider's first-party list rates, verified October 17, 2026 and October 17, 2026.
What are the context windows of Gemini 2.5 Pro and Gemini 3.1 Pro Preview?
Gemini 2.5 Pro and Gemini 3.1 Pro Preview both have a 1,048,576-token context window, and both return up to 65,536 output tokens per response.
Are Gemini 2.5 Pro and Gemini 3.1 Pro Preview open weights?
Gemini 2.5 Pro is closed-weights and is called through Google's API as gemini-2.5-pro. Gemini 3.1 Pro Preview is closed-weights and is called through Google's API as gemini-3.1-pro-preview.
More comparisons
Sources
Gemini 2.5 Pro verified from ai.google.dev; Gemini 3.1 Pro Preview verified from ai.google.dev. This page is as current as the older of the two: .
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