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GPT-5.2 Pro vs Grok-4 Heavy

Both models are evenly matched across the benchmarks.

OpenAI · xAI · Updated for 2026

Which is better?

GPT-5.2 Pro outperforms in 1 benchmarks (GPQA), while Grok-4 Heavy is better at 1 benchmark (Humanity's Last Exam). Both models are evenly matched across the benchmarks.

Based on current benchmark, pricing, and model metadata for 2026.

Choose GPT-5.2 Pro

  • you want predictable pricing at $21.00/M input and $168.00/M output

Choose Grok-4 Heavy

  • you want the strongest raw capability — it leads on 2 of 3 shared benchmarks

At a glance

The differences that matter most.

Benchmark wins
1 of 3
2 of 3
Input price
$21.00 / M
— / M
Output price
$168.00 / M
— / M
Context window
400,000
Released
Dec 2025
License
Proprietary
Proprietary

Performance Benchmarks

Comparative analysis across standard metrics

3 benchmarks

GPT-5.2 Pro outperforms in 1 benchmarks (GPQA), while Grok-4 Heavy is better at 1 benchmark (Humanity's Last Exam).

Both models are evenly matched across the benchmarks.

Tue Aug 25 2026 • llm-stats.com

Arena Performance

Playground indexes and blind preference scores

Context Window

Maximum input and output token capacity

Only GPT-5.2 Pro specifies input context (400,000 tokens). Only GPT-5.2 Pro specifies output context (128,000 tokens).

OpenAI
GPT-5.2 Pro
Input400,000 tokens
Output128,000 tokens
xAI
Grok-4 Heavy
Input- tokens
Output- tokens
Tue Aug 25 2026 • llm-stats.com

Input Capabilities

Supported data types and modalities

Both GPT-5.2 Pro and Grok-4 Heavy support multimodal inputs.

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

GPT-5.2 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.

GPT-5.2 Pro

Proprietary

Closed source

Grok-4 Heavy

Proprietary

Closed source

Release Timeline

When each model was launched

GPT-5.2 Pro was released on 2025-12-11, while Grok-4 Heavy's release date is not specified.

We can confirm GPT-5.2 Pro's release timeline, but cannot make a direct age comparison without Grok-4 Heavy's release date.

GPT-5.2 Pro

Dec 11, 2025

8 months ago

Grok-4 Heavy

Knowledge Cutoff

When training data ends

Grok-4 Heavy has a documented knowledge cutoff of 2024-12-31, while GPT-5.2 Pro'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 GPT-5.2 Pro's cutoff date.

GPT-5.2 Pro

Grok-4 Heavy

Dec 2024

Outputs Comparison

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Judge for yourself.

Run your own prompts against GPT-5.2 Pro and Grok-4 Heavy side-by-side, then vote on the output you prefer.

GPT-5.2 Pro
✓ Preferred
Grok-4 Heavy
Open in Playground

FAQ

Common questions about GPT-5.2 Pro vs Grok-4 Heavy.

Which is better, GPT-5.2 Pro or Grok-4 Heavy?

Both models are evenly matched across the benchmarks. GPT-5.2 Pro is made by OpenAI 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 GPT-5.2 Pro compare to Grok-4 Heavy in benchmarks?

GPT-5.2 Pro scores AIME 2025: 100.0%, HMMT 2025: 100.0%, GPQA: 93.2%, ARC-AGI: 90.5%, BrowseComp: 77.9%. 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 GPT-5.2 Pro and Grok-4 Heavy?

GPT-5.2 Pro supports 400K 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.

Who makes GPT-5.2 Pro and Grok-4 Heavy?

GPT-5.2 Pro is developed by OpenAI and Grok-4 Heavy is developed by xAI.