Google: Gemini 3.1 Pro (Preview Low)
Gemini 3.1 Pro (Preview Low) is a reasoning model from Google released on Feb 21, 2026. It reads text, images and audio and writes text, with a 1.05M token context window and up to 66K tokens per reply.
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It costs $2 per million input tokens and $12 per million output tokens. Cached input bills at $0.20, 90% less than fresh input.
It supports tool calling, structured JSON output and prompt caching.
- Modalities
- In / out price
- $2 / $12 per 1M
- Context
- 1.05M
- Max output
- 66K
- Released
- Feb 21, 2026
- Knowledge cutoff
- n/a
- Tool calling
- Structured output
- Reasoning
- Prompt caching
- Open weights
- Free to use
Gemini 3.1 Pro (Preview Low) pricing
USD, as listed on Oct 15, 2026. Most bills are input heavy, so the cached input rate matters as much as the headline price.
| Input | $2 / 1M tokens | |
|---|---|---|
| Output | $12 / 1M tokens | |
| Cached input (read) | $0.20 / 1M tokens | 90% off input |
| Cache write | $0.375 / 1M tokens |
What Gemini 3.1 Pro (Preview Low) costs per month
Pick a workload close to yours or type your own volumes.
Supported request parameters
What you can set when you call Gemini 3.1 Pro (Preview Low) through an OpenAI compatible API.
- Tools
tools - Structured outputs
structured_outputs - Reasoning
reasoning
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Gemini 3.1 Pro (Preview Low) questions
How much does the Gemini 3.1 Pro (Preview Low) API cost?
$2 per million input tokens and $12 per million output tokens, with cached input at $0.20. The estimator on this page turns that into a monthly bill for your own workload.
What is the context window of Gemini 3.1 Pro (Preview Low)?
1,048,576 tokens of input, and it can write up to 65,536 tokens in one reply. As a rough guide, a million tokens is around 750,000 English words.
Does Gemini 3.1 Pro (Preview Low) support tool calling?
Yes. It accepts tool definitions and can return JSON that matches a schema, which is what an agent needs to call your APIs.
Is Gemini 3.1 Pro (Preview Low) open source?
No. Google serves it through an API only, so you cannot download the weights or host it yourself.
When was Gemini 3.1 Pro (Preview Low) released?
Feb 21, 2026.
Catalog data from models.dev (MIT licensed), refreshed daily, last on Oct 15, 2026. The summary is written from these facts.
Building on Gemini 3.1 Pro (Preview Low)?
I test your real tasks on it and the two closest alternatives, then ship the agent on whichever wins on cost and accuracy.
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