Overview
Gemini 3 Pro is Google DeepMind's flagship, and the model many reviewers describe as the biggest leap since the original GPT-4 moment. Launched in November 2025 with a 1M-token context window and a 64K output window, it surged to the top of LMArena on release and posted standout scores on reasoning benchmarks — AIME, GPQA, Humanity's Last Exam, LiveCodeBench Pro and more — that Gemini 2.5 couldn't touch.
Its real superpower is multimodal reasoning over huge inputs: long documents, codebases, video and images analysed together with a depth competitors struggle to match. Gemini 3 Pro is the model that put Google decisively back at the frontier and triggered OpenAI's "code red" response, and the 3.1 Pro refresh has since pushed its reasoning and multimodal scores even higher.
Key capabilities
- 1M-token context, 64K-token output
- Top-tier reasoning and multimodal benchmarks
- Excellent image-plus-reasoning performance
- Briefly #1 overall on LMArena at launch
At a glance
Context
1M tokens
Output
64K tokens
LMArena
#1 at launch
Pricing: Premium frontier tier; cheaper Flash variant available.
Pros & cons
What we like
- Massive 1M-token context window
- Class-leading multimodal and reasoning scores
- Strong on math, science and competitive coding
Trade-offs
- Premium pricing for the Pro tier
- Quality can be uneven outside its strongest categories
The verdict
Gemini 3 Pro is a genuine frontier model and the best choice for long-context and multimodal reasoning — analysing whole codebases, documents or video in one pass. It put Google back on top in late 2025, and it's the model to beat for anyone whose work lives at huge context lengths.
Best for: Long-context and multimodal reasoning at the frontier.
Frequently asked questions
How big is Gemini 3 Pro's context window?
1 million tokens of input with up to 64K tokens of output, making it ideal for analysing whole documents, codebases or long videos in a single pass.
Is Gemini 3 Pro better than GPT-5.2?
They trade blows. Gemini 3 Pro leads on long-context and multimodal reasoning; GPT-5.2 is prized for agentic tool use and document work. Comparing them side-by-side on your own prompts is the best way to decide.