Model Comparison

Gemini 2.5 Flash-Lite vs Grok-4 HeavyWhich is better in 2026?

Grok-4 Heavy significantly outperforms across most benchmarks.

Verdict: Gemini 2.5 Flash-Lite vs Grok-4 Heavy — which is better?

Gemini 2.5 Flash-Lite (by Google) and Grok-4 Heavy (by xAI) are two of the AI models people compare most. Here is how they stack up on benchmarks, price and capabilities, and which one to pick in 2026.

Gemini 2.5 Flash-Lite outperforms in 0 benchmarks, while Grok-4 Heavy is better at 4 benchmarks (AIME 2025, GPQA, Humanity's Last Exam, LiveCodeBench). Grok-4 Heavy significantly outperforms across most benchmarks.

Choose Gemini 2.5 Flash-Lite if…

  • you need open weights you can self-host or fine-tune

Choose Grok-4 Heavy if…

  • you want the strongest raw capability — it leads on 4 of 4 shared benchmarks
Want to compare interactively?Try the playground

Performance Benchmarks

Comparative analysis across standard metrics

4 benchmarks

Gemini 2.5 Flash-Lite outperforms in 0 benchmarks, while Grok-4 Heavy is better at 4 benchmarks (AIME 2025, GPQA, Humanity's Last Exam, LiveCodeBench).

Grok-4 Heavy significantly outperforms across most benchmarks.

Fri Jun 12 2026 • llm-stats.com

Arena Performance

Human preference votes

Context Window

Maximum input and output token capacity

Only Gemini 2.5 Flash-Lite specifies input context (1,048,576 tokens). Only Gemini 2.5 Flash-Lite specifies output context (65,536 tokens).

Google
Gemini 2.5 Flash-Lite
Input1,048,576 tokens
Output65,536 tokens
xAI
Grok-4 Heavy
Input- tokens
Output- tokens
Fri Jun 12 2026 • llm-stats.com

Input Capabilities

Supported data types and modalities

Both Gemini 2.5 Flash-Lite and Grok-4 Heavy support multimodal inputs.

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

Gemini 2.5 Flash-Lite

Text
Images
Audio
Video

Grok-4 Heavy

Text
Images
Audio
Video

License

Usage and distribution terms

Gemini 2.5 Flash-Lite is licensed under Creative Commons Attribution 4.0 License, while Grok-4 Heavy uses a proprietary license.

License differences may affect how you can use these models in commercial or open-source projects.

Gemini 2.5 Flash-Lite

Creative Commons Attribution 4.0 License

Open weights

Grok-4 Heavy

Proprietary

Closed source

Release Timeline

When each model was launched

Gemini 2.5 Flash-Lite was released on 2025-06-17, while Grok-4 Heavy's release date is not specified.

We can confirm Gemini 2.5 Flash-Lite's release timeline, but cannot make a direct age comparison without Grok-4 Heavy's release date.

Gemini 2.5 Flash-Lite

Jun 17, 2025

12 months ago

Grok-4 Heavy

—

Knowledge Cutoff

When training data ends

Gemini 2.5 Flash-Lite has a knowledge cutoff of 2025-01-01, while Grok-4 Heavy has a cutoff of 2024-12-31.

Gemini 2.5 Flash-Lite has more recent training data (up to 2025-01-01), making it potentially better informed about events through that date compared to Grok-4 Heavy (2024-12-31).

Gemini 2.5 Flash-Lite

Jan 2025

1 mo newer
Grok-4 Heavy

Dec 2024

Outputs Comparison

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Key Takeaways

Google
Larger context window (1,048,576 tokens)
Has open weights
xAI
Higher AIME 2025 score (100.0% vs 49.8%)
Higher GPQA score (88.4% vs 64.6%)
Higher Humanity's Last Exam score (50.7% vs 5.1%)
Higher LiveCodeBench score (79.4% vs 33.7%)

Detailed Comparison

AI Model Comparison Table
Feature
Google
Gemini 2.5 Flash-Lite
xAI
Grok-4 Heavy

FAQ

Common questions about Gemini 2.5 Flash-Lite vs Grok-4 Heavy.

Which is better, Gemini 2.5 Flash-Lite or Grok-4 Heavy?

Grok-4 Heavy significantly outperforms across most benchmarks. Gemini 2.5 Flash-Lite is made by Google and Grok-4 Heavy is made by xAI. The best choice depends on your use case — compare their benchmark scores, pricing, and capabilities above.

How does Gemini 2.5 Flash-Lite compare to Grok-4 Heavy in benchmarks?

Gemini 2.5 Flash-Lite scores FACTS Grounding: 84.1%, Global-MMLU-Lite: 81.1%, MMMU: 72.9%, GPQA: 64.6%, Vibe-Eval: 51.3%. 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 2.5 Flash-Lite and Grok-4 Heavy?

Gemini 2.5 Flash-Lite 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 2.5 Flash-Lite and Grok-4 Heavy?

Key differences include licensing (Creative Commons Attribution 4.0 License vs Proprietary). See the full comparison above for benchmark-by-benchmark results.

Who makes Gemini 2.5 Flash-Lite and Grok-4 Heavy?

Gemini 2.5 Flash-Lite is developed by Google and Grok-4 Heavy is developed by xAI.

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