Model Comparison

GLM-4.5-Air vs Grok-4 HeavyWhich is better in 2026?

Grok-4 Heavy significantly outperforms across most benchmarks.

Verdict: GLM-4.5-Air vs Grok-4 Heavy — which is better?

GLM-4.5-Air (by Zhipu AI) 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.

GLM-4.5-Air outperforms in 0 benchmarks, while Grok-4 Heavy is better at 3 benchmarks (GPQA, Humanity's Last Exam, LiveCodeBench). Grok-4 Heavy significantly outperforms across most benchmarks.

Choose GLM-4.5-Air 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 3 of 3 shared benchmarks
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Performance Benchmarks

Comparative analysis across standard metrics

3 benchmarks

GLM-4.5-Air outperforms in 0 benchmarks, while Grok-4 Heavy is better at 3 benchmarks (GPQA, Humanity's Last Exam, LiveCodeBench).

Grok-4 Heavy significantly outperforms across most benchmarks.

Sun Jun 14 2026 • llm-stats.com

Arena Performance

Human preference votes

Input Capabilities

Supported data types and modalities

Grok-4 Heavy supports multimodal inputs, whereas GLM-4.5-Air does not.

Grok-4 Heavy can handle both text and other forms of data like images, making it suitable for multimodal applications.

GLM-4.5-Air

Text
Images
Audio
Video

Grok-4 Heavy

Text
Images
Audio
Video

License

Usage and distribution terms

GLM-4.5-Air is licensed under MIT, while Grok-4 Heavy uses a proprietary license.

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

GLM-4.5-Air

MIT

Open weights

Grok-4 Heavy

Proprietary

Closed source

Release Timeline

When each model was launched

GLM-4.5-Air was released on 2025-07-28, while Grok-4 Heavy's release date is not specified.

We can confirm GLM-4.5-Air's release timeline, but cannot make a direct age comparison without Grok-4 Heavy's release date.

GLM-4.5-Air

Jul 28, 2025

10 months ago

Grok-4 Heavy

—

Knowledge Cutoff

When training data ends

Grok-4 Heavy has a documented knowledge cutoff of 2024-12-31, while GLM-4.5-Air's cutoff date is not specified.

We can confirm Grok-4 Heavy's training data extends to 2024-12-31, but cannot make a direct comparison without GLM-4.5-Air's cutoff date.

GLM-4.5-Air

—

Grok-4 Heavy

Dec 2024

Outputs Comparison

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Key Takeaways

Zhipu AI
Has open weights
xAI
Supports multimodal inputs
Higher GPQA score (88.4% vs 75.0%)
Higher Humanity's Last Exam score (50.7% vs 10.6%)
Higher LiveCodeBench score (79.4% vs 70.7%)

Detailed Comparison

AI Model Comparison Table
Feature
Zhipu AI
GLM-4.5-Air
xAI
Grok-4 Heavy

FAQ

Common questions about GLM-4.5-Air vs Grok-4 Heavy.

Which is better, GLM-4.5-Air or Grok-4 Heavy?

Grok-4 Heavy significantly outperforms across most benchmarks. GLM-4.5-Air is made by Zhipu AI 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 GLM-4.5-Air compare to Grok-4 Heavy in benchmarks?

GLM-4.5-Air scores MATH-500: 98.1%, AIME 2024: 89.4%, MMLU-Pro: 81.4%, TAU-bench Retail: 77.9%, BFCL-v3: 76.4%. Grok-4 Heavy scores AIME 2025: 100.0%, HMMT25: 96.7%, GPQA: 88.4%, LiveCodeBench: 79.4%, USAMO25: 61.9%.

What are the main differences between GLM-4.5-Air and Grok-4 Heavy?

Key differences include multimodal support (no vs yes), licensing (MIT vs Proprietary). See the full comparison above for benchmark-by-benchmark results.

Who makes GLM-4.5-Air and Grok-4 Heavy?

GLM-4.5-Air is developed by Zhipu AI and Grok-4 Heavy is developed by xAI.

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