Model Comparison

Claude Opus 4.6 vs Grok-4 Heavy

Claude Opus 4.6 shows notably better performance in the majority of benchmarks.

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Performance Benchmarks

Comparative analysis across standard metrics

3 benchmarks

Claude Opus 4.6 outperforms in 2 benchmarks (GPQA, Humanity's Last Exam), while Grok-4 Heavy is better at 1 benchmark (AIME 2025).

Claude Opus 4.6 shows notably better performance in the majority of benchmarks.

Sun May 24 2026 • llm-stats.com

Arena Performance

Human preference votes

Context Window

Maximum input and output token capacity

Only Claude Opus 4.6 specifies input context (1,000,000 tokens). Only Claude Opus 4.6 specifies output context (128,000 tokens).

Anthropic
Claude Opus 4.6
Input1,000,000 tokens
Output128,000 tokens
xAI
Grok-4 Heavy
Input- tokens
Output- tokens
Sun May 24 2026 • llm-stats.com

Input Capabilities

Supported data types and modalities

Both Claude Opus 4.6 and Grok-4 Heavy support multimodal inputs.

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

Claude Opus 4.6

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.

Claude Opus 4.6

Proprietary

Closed source

Grok-4 Heavy

Proprietary

Closed source

Release Timeline

When each model was launched

Claude Opus 4.6 was released on 2026-02-05, while Grok-4 Heavy's release date is not specified.

We can confirm Claude Opus 4.6's release timeline, but cannot make a direct age comparison without Grok-4 Heavy's release date.

Claude Opus 4.6

Feb 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 Claude Opus 4.6'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 Claude Opus 4.6's cutoff date.

Claude Opus 4.6

—

Grok-4 Heavy

Dec 2024

Outputs Comparison

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Key Takeaways

Anthropic
Larger context window (1,000,000 tokens)
Higher GPQA score (91.3% vs 88.4%)
Higher Humanity's Last Exam score (53.1% vs 50.7%)
xAI
Higher AIME 2025 score (100.0% vs 99.8%)

Detailed Comparison

AI Model Comparison Table
Feature
Anthropic
Claude Opus 4.6
xAI
Grok-4 Heavy

FAQ

Common questions about Claude Opus 4.6 vs Grok-4 Heavy.

Which is better, Claude Opus 4.6 or Grok-4 Heavy?

Claude Opus 4.6 shows notably better performance in the majority of benchmarks. Claude Opus 4.6 is made by Anthropic 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 Claude Opus 4.6 compare to Grok-4 Heavy in benchmarks?

Claude Opus 4.6 scores Vending-Bench 2: 100.0%, AIME 2025: 99.8%, Tau2 Telecom: 99.3%, Graphwalks parents >128k: 95.4%, MRCR v2 (8-needle): 93.0%. 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 Claude Opus 4.6 and Grok-4 Heavy?

Claude Opus 4.6 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 Claude Opus 4.6 and Grok-4 Heavy?

Claude Opus 4.6 is developed by Anthropic and Grok-4 Heavy is developed by xAI.