Model Comparison

Claude 3.5 Sonnet vs Grok-4 Heavy

Grok-4 Heavy significantly outperforms across most benchmarks.

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Performance Benchmarks

Comparative analysis across standard metrics

1 benchmarks

Claude 3.5 Sonnet outperforms in 0 benchmarks, while Grok-4 Heavy is better at 1 benchmark (GPQA).

Grok-4 Heavy significantly outperforms across most benchmarks.

Tue May 12 2026 • llm-stats.com

Arena Performance

Human preference votes

Context Window

Maximum input and output token capacity

Only Claude 3.5 Sonnet specifies input context (200,000 tokens). Only Claude 3.5 Sonnet specifies output context (200,000 tokens).

Anthropic
Claude 3.5 Sonnet
Input200,000 tokens
Output200,000 tokens
xAI
Grok-4 Heavy
Input- tokens
Output- tokens
Tue May 12 2026 • llm-stats.com

Input Capabilities

Supported data types and modalities

Both Claude 3.5 Sonnet and Grok-4 Heavy support multimodal inputs.

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

Claude 3.5 Sonnet

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 3.5 Sonnet

Proprietary

Closed source

Grok-4 Heavy

Proprietary

Closed source

Release Timeline

When each model was launched

Claude 3.5 Sonnet was released on 2024-10-22, while Grok-4 Heavy's release date is not specified.

We can confirm Claude 3.5 Sonnet's release timeline, but cannot make a direct age comparison without Grok-4 Heavy's release date.

Claude 3.5 Sonnet

Oct 22, 2024

1.6 years ago

Grok-4 Heavy

—

Knowledge Cutoff

When training data ends

Grok-4 Heavy has a documented knowledge cutoff of 2024-12-31, while Claude 3.5 Sonnet'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 3.5 Sonnet's cutoff date.

Claude 3.5 Sonnet

—

Grok-4 Heavy

Dec 2024

Outputs Comparison

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Key Takeaways

Anthropic
Larger context window (200,000 tokens)
xAI
Higher GPQA score (88.4% vs 67.2%)

Detailed Comparison

AI Model Comparison Table
Feature
Anthropic
Claude 3.5 Sonnet
xAI
Grok-4 Heavy

FAQ

Common questions about Claude 3.5 Sonnet vs Grok-4 Heavy.

Which is better, Claude 3.5 Sonnet or Grok-4 Heavy?

Grok-4 Heavy significantly outperforms across most benchmarks. Claude 3.5 Sonnet 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 3.5 Sonnet compare to Grok-4 Heavy in benchmarks?

Claude 3.5 Sonnet scores GSM8k: 96.4%, DocVQA: 95.2%, AI2D: 94.7%, HumanEval: 93.7%, BIG-Bench Hard: 93.1%. 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 3.5 Sonnet and Grok-4 Heavy?

Claude 3.5 Sonnet supports 200K 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 3.5 Sonnet and Grok-4 Heavy?

Claude 3.5 Sonnet is developed by Anthropic and Grok-4 Heavy is developed by xAI.