Overview
Gemini 3.1 Pro is Google DeepMind's first major refresh of the Gemini 3 Pro line, pushing its already-strong reasoning and multimodal scores higher. It keeps the 1-million-token context window and 64K output window of its predecessor and tightens performance on GPQA, AIME and LiveCodeBench — the benchmark suites where Gemini 3 first made its name.
Its superpower remains multimodal reasoning over huge inputs: long documents, whole codebases, images and video analysed together at a depth rivals struggle to match. With Gemini 3.5 Pro rumoured next, 3.1 Pro is the current Pro-tier default for the most demanding long-context and multi-modal work.
Key capabilities
- 1M-token context, 64K-token output
- Improved reasoning over Gemini 3 Pro
- Top-tier multimodal and coding benchmarks
- Strong on GPQA, AIME and LiveCodeBench
At a glance
Context
1M tokens
Output
64K tokens
GPQA
~94%
Pricing: Premium frontier tier; cheaper Flash variant available.
Pros & cons
What we like
- Massive 1M-token context window
- Best-in-class multimodal reasoning
- Genuine gains over Gemini 3 Pro
Trade-offs
- Premium Pro-tier pricing
- Quality can be uneven outside its strongest categories
- Gemini 3.5 Pro expected soon
The verdict
Gemini 3.1 Pro is the refined frontier pick for long-context and multimodal reasoning — analysing whole codebases, documents or video in one pass. It tightens Gemini 3 Pro's strengths and is the model to beat at huge context lengths, even as everyone waits for 3.5 Pro.
Best for: Long-context and multimodal reasoning at the frontier.
Frequently asked questions
How is Gemini 3.1 Pro different from 3 Pro?
It's a refresh of Gemini 3 Pro with improved reasoning and multimodal scores — better on GPQA, AIME and LiveCodeBench — while keeping the same 1M context and 64K output windows.
Is Gemini 3.1 Pro better than GPT-5.5?
They trade blows. Gemini 3.1 Pro leads on long-context and multimodal reasoning; GPT-5.5 is prized for agentic tool use and reliability. Comparing them side-by-side on your own prompts is the best way to decide.