Model Comparison

GPT-5.4 vs Grok-4 HeavyWhich is better in 2026?

Both models are evenly matched across the benchmarks.

Verdict: GPT-5.4 vs Grok-4 Heavy — which is better?

GPT-5.4 (by OpenAI) 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.

GPT-5.4 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.

Choose GPT-5.4 if…

  • you want predictable pricing at $2.50/M input and $15.00/M output

Choose Grok-4 Heavy if…

  • you are already invested in the xAI ecosystem
Want to compare interactively?Try the playground

Performance Benchmarks

Comparative analysis across standard metrics

2 benchmarks

GPT-5.4 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.

Sat Jun 06 2026 • llm-stats.com

Arena Performance

Human preference votes

Context Window

Maximum input and output token capacity

Only GPT-5.4 specifies input context (1,000,000 tokens). Only GPT-5.4 specifies output context (128,000 tokens).

OpenAI
GPT-5.4
Input1,000,000 tokens
Output128,000 tokens
xAI
Grok-4 Heavy
Input- tokens
Output- tokens
Sat Jun 06 2026 • llm-stats.com

Input Capabilities

Supported data types and modalities

Both GPT-5.4 and Grok-4 Heavy support multimodal inputs.

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

GPT-5.4

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-5.4

Proprietary

Closed source

Grok-4 Heavy

Proprietary

Closed source

Release Timeline

When each model was launched

GPT-5.4 was released on 2026-03-05, while Grok-4 Heavy's release date is not specified.

We can confirm GPT-5.4's release timeline, but cannot make a direct age comparison without Grok-4 Heavy's release date.

GPT-5.4

Mar 5, 2026

3 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-5.4'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-5.4's cutoff date.

GPT-5.4

—

Grok-4 Heavy

Dec 2024

Outputs Comparison

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Key Takeaways

OpenAI
Larger context window (1,000,000 tokens)
Higher GPQA score (92.8% vs 88.4%)
xAI
Higher Humanity's Last Exam score (50.7% vs 39.8%)

Detailed Comparison

AI Model Comparison Table
Feature
OpenAI
GPT-5.4
xAI
Grok-4 Heavy

FAQ

Common questions about GPT-5.4 vs Grok-4 Heavy.

Which is better, GPT-5.4 or Grok-4 Heavy?

Both models are evenly matched across the benchmarks. GPT-5.4 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-5.4 compare to Grok-4 Heavy in benchmarks?

GPT-5.4 scores Tau2 Telecom: 98.9%, ARC-AGI: 93.7%, Graphwalks BFS <128k: 93.0%, GPQA: 92.8%, Graphwalks parents <128k: 89.8%. 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-5.4 and Grok-4 Heavy?

GPT-5.4 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.

Who makes GPT-5.4 and Grok-4 Heavy?

GPT-5.4 is developed by OpenAI and Grok-4 Heavy is developed by xAI.

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