Gemini 3.1 Pro vs Grok 4 Fast Comparison
Comparing Gemini 3.1 Pro and Grok 4 Fast across benchmarks, pricing, and capabilities.
Performance Benchmarks
Comparative analysis across standard metrics
Gemini 3.1 Pro outperforms in 3 benchmarks (BrowseComp, GPQA, Humanity's Last Exam), while Grok 4 Fast is better at 0 benchmarks.
Gemini 3.1 Pro significantly outperforms across most benchmarks.
Arena Performance
Human preference votes
Pricing Analysis
Price comparison per million tokens
For input processing, Gemini 3.1 Pro ($2.50/1M tokens) is 12.5x more expensive than Grok 4 Fast ($0.20/1M tokens).
For output processing, Gemini 3.1 Pro ($15.00/1M tokens) is 30.0x more expensive than Grok 4 Fast ($0.50/1M tokens).
In conclusion, Gemini 3.1 Pro is more expensive than Grok 4 Fast.*
* Using a 3:1 ratio of input to output tokens
Context Window
Maximum input and output token capacity
Grok 4 Fast accepts 2,000,000 input tokens compared to Gemini 3.1 Pro's 1,048,576 tokens. Gemini 3.1 Pro can generate longer responses up to 65,536 tokens, while Grok 4 Fast is limited to 30,000 tokens.
Input Capabilities
Supported data types and modalities
Both Gemini 3.1 Pro and Grok 4 Fast support multimodal inputs.
They are both capable of processing various types of data, offering versatility in application.
Gemini 3.1 Pro
Grok 4 Fast
License
Usage and distribution terms
Both models are licensed under proprietary licenses.
Both models have usage restrictions defined by their respective organizations.
Proprietary
Closed source
Proprietary
Closed source
Release Timeline
When each model was launched
Gemini 3.1 Pro was released on 2026-02-19, while Grok 4 Fast was released on 2025-08-28.
Gemini 3.1 Pro is 6 months newer than Grok 4 Fast.
Feb 19, 2026
3 weeks ago
5mo newerAug 28, 2025
6 months ago
Knowledge Cutoff
When training data ends
Gemini 3.1 Pro has a documented knowledge cutoff of 2025-01-31, while Grok 4 Fast's cutoff date is not specified.
We can confirm Gemini 3.1 Pro's training data extends to 2025-01-31, but cannot make a direct comparison without Grok 4 Fast's cutoff date.
Jan 2025
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Provider Availability
Gemini 3.1 Pro is available from Google. Grok 4 Fast is available from xAI. The availability of providers can affect quality of the model and reliability.
Gemini 3.1 Pro
Grok 4 Fast
Outputs Comparison
Key Takeaways
Detailed Comparison
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