How much does the Gemini 3.1 Pro API cost?

Gemini 3.1 Pro costs $2 per million input tokens and $12 per million output tokens, with cached input at $0.2 per million. A workload of 10M input and 1.5M output tokens per month costs about $38.00.

What is the context window of Gemini 3.1 Pro?

Gemini 3.1 Pro supports a context window of 2,000,000 tokens (2M), with up to 66K output tokens per response.

Is Gemini 3.1 Pro open source?

No — Gemini 3.1 Pro is a proprietary model available through Google's API and partner platforms.

What are the best alternatives to Gemini 3.1 Pro?

The closest alternatives by overall capability are Qwen3-Max, GPT-5.5, GPT-5, OpenAI o3. See the comparison pages for detailed head-to-head breakdowns.

Gemini 3.1 Pro

Name: Gemini 3.1 Pro
Price: 2 USD
Author: Google

Google·Mar 2026reasoningproprietary

Gemini 3.1 Pro is Google's top generally-available model and the context-window leader of the frontier: 2 million tokens, enough for entire codebases, hours of video or thousands of pages in a single prompt. Long-context prompts above 200K tokens carry a pricing premium, and batch processing halves costs. For multimodal analysis and massive-context retrieval workloads it is the strongest option on the market.

Benchmark results

SWE-bench VerifiedCoding · #11 of 33~78%

Where it shines

2M-token context — the largest of any frontier model
State-of-the-art video, audio and document understanding
Aggressive $2/$12 pricing for a flagship

Alternatives to Gemini 3.1 Pro

Qwen3-Max

Alibaba's trillion-parameter API flagship — frontier-adjacent quality with strong agentic tool use at mid-tier prices.

GPT-5.5

OpenAI's flagship reasoning model with a 1M-token context window, built for hard coding, science and long-horizon agentic work.

GPT-5

OpenAI's August 2025 unified flagship that merged the GPT and o-series reasoning lines into one model with selectable effort.

OpenAI o3

OpenAI's dedicated 2025 reasoning model that pioneered thinking-with-images and agentic tool use within chain-of-thought.

Frequently asked questions

How much does the Gemini 3.1 Pro API cost?: Gemini 3.1 Pro costs $2 per million input tokens and $12 per million output tokens, with cached input at $0.2 per million. A workload of 10M input and 1.5M output tokens per month costs about $38.00.
What is the context window of Gemini 3.1 Pro?: Gemini 3.1 Pro supports a context window of 2,000,000 tokens (2M), with up to 66K output tokens per response.
Is Gemini 3.1 Pro open source?: No — Gemini 3.1 Pro is a proprietary model available through Google's API and partner platforms.
What are the best alternatives to Gemini 3.1 Pro?: The closest alternatives by overall capability are Qwen3-Max, GPT-5.5, GPT-5, OpenAI o3. See the comparison pages for detailed head-to-head breakdowns.