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Gemini 3.1 Pro vs Grok-4 Heavy

Gemini 3.1 Pro and Grok-4 Heavy are closely matched at 43.2 and 40.7 on the LLM Stats Score.

Google · xAI · Updated for 2026

Which is better?

Gemini 3.1 Pro and Grok-4 Heavy are closely matched on the overall LLM Stats Score at 43.2 and 40.7.

In the 2 individual benchmarks reported for both models, Gemini 3.1 Pro wins 2; this is a narrower head-to-head signal than the composite indexes.

Based on current LLM Stats indexes, shared benchmarks, pricing, and model metadata for 2026.

Choose Gemini 3.1 Pro

  • you value its reported benchmark strengths — it wins 2 of 2 exact shared results

Choose Grok-4 Heavy

  • you are already invested in the xAI ecosystem

At a glance

The differences that matter most.

Gemini 3.1 Pro
Google
Grok-4 Heavy
xAI
Core performance indexes
LLM Stats Score
43.2
#47
40.7
#61
Reasoning
44.9
#34
39.0
#65
Coding
30.7
#50
17.7
#123
Cost, coverage & limits
Benchmark wins
2 of 2
0 of 2
Input price
$2.00 / M
— / M
Output price
$12.00 / M
— / M
Context window
1,000,000
—

Capability indexes

Additional strengths measured across groups of related public benchmarks

1 shared
Index
Gemini 3.1 Pro
Grok-4 Heavy
Math
42.4#6
41.5#7
Conservative TrueSkill rating · higher is betterHow scores work

Individual benchmarks

20 reported for Gemini 3.1 Pro · 6 for Grok-4 Heavy

2 shared

Gemini 3.1 Pro outperforms in 2 benchmarks (GPQA, Humanity's Last Exam), while Grok-4 Heavy is better at 0 benchmarks.

Gemini 3.1 Pro significantly outperforms across most benchmarks.

Mon Oct 05 2026 • llm-stats.com

Human preference

Blind head-to-head votes and playground preference scores

Context Window

Maximum input and output token capacity

Only Gemini 3.1 Pro specifies input context (1,000,000 tokens). Only Gemini 3.1 Pro specifies output context (1,000,000 tokens).

Google
Gemini 3.1 Pro
Input1,000,000 tokens
Output1,000,000 tokens
xAI
Grok-4 Heavy
Input- tokens
Output- tokens
Mon Oct 05 2026 • llm-stats.com

Input capabilities

Documented input modalities across available providers

Both Gemini 3.1 Pro and Grok-4 Heavy support multimodal inputs.

They are both capable of processing various types of data, offering versatility in application.

Gemini 3.1 Pro

Text
Images
Audio
Video

Grok-4 Heavy

Text
Images
Audio
Video

License

Usage and distribution terms

Both models are licensed under proprietary licenses.

Both models have usage restrictions defined by their respective organizations.

Gemini 3.1 Pro

Proprietary

Closed source

Grok-4 Heavy

Proprietary

Closed source

Release Timeline

When each model was launched

Gemini 3.1 Pro was released on 2026-02-19, while Grok-4 Heavy's release date is not specified.

We can confirm Gemini 3.1 Pro's release timeline, but cannot make a direct age comparison without Grok-4 Heavy's release date.

Gemini 3.1 Pro

Feb 19, 2026

7 months ago

Grok-4 Heavy

—

Knowledge Cutoff

When training data ends

Gemini 3.1 Pro has a knowledge cutoff of 2025-01-31, while Grok-4 Heavy has a cutoff of 2024-12-31.

Gemini 3.1 Pro has more recent training data (up to 2025-01-31), making it potentially better informed about events through that date compared to Grok-4 Heavy (2024-12-31).

Gemini 3.1 Pro

Jan 2025

1 mo newer
Grok-4 Heavy

Dec 2024

Outputs Comparison

Notice missing or incorrect data?

Judge for yourself.

Run your own prompts against Gemini 3.1 Pro and Grok-4 Heavy side-by-side, then vote on the output you prefer.

Gemini 3.1 Pro
✓ Preferred
Grok-4 Heavy
Open in Playground

FAQ

Common questions about Gemini 3.1 Pro vs Grok-4 Heavy.

Which is better, Gemini 3.1 Pro or Grok-4 Heavy?

Gemini 3.1 Pro and Grok-4 Heavy are closely matched on the LLM Stats Score at 43.2 and 40.7. Gemini 3.1 Pro is made by Google and Grok-4 Heavy is made by xAI. The best choice depends on your use case — compare their capability indexes, individual benchmarks, pricing, and limits above.

How does Gemini 3.1 Pro compare to Grok-4 Heavy in benchmarks?

Gemini 3.1 Pro scores t2-bench: 99.3%, LiveCodeBench Pro: 96.2%, GPQA: 94.3%, MMMLU: 92.6%, BrowseComp: 85.9%. Grok-4 Heavy scores AIME 2025: 100.0%, HMMT25: 96.7%, GPQA: 88.4%, LiveCodeBench: 79.4%, USAMO25: 61.9%.

What are the context window sizes for Gemini 3.1 Pro and Grok-4 Heavy?

Gemini 3.1 Pro supports 1.0M tokens and Grok-4 Heavy supports an unknown number of tokens. A larger context window lets you process longer documents, conversations, or codebases in a single request.

What are the main differences between Gemini 3.1 Pro and Grok-4 Heavy?

Key differences include LLM Stats Score (43.2 vs 40.7). See the full comparison above for benchmark-by-benchmark results.

Who makes Gemini 3.1 Pro and Grok-4 Heavy?

Gemini 3.1 Pro is developed by Google and Grok-4 Heavy is developed by xAI.

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