Claude Sonnet 4.5 vs Grok 3 Thinking

Compare Claude Sonnet 4.5 by Anthropic against Grok 3 Thinking by xAI, context windows of 200K vs 128K, tested across 13 shared challenges. Updated April 2026.

Which is better, Claude Sonnet 4.5 or Grok 3 Thinking?

Claude Sonnet 4.5 and Grok 3 Thinking are both competitive models. Context windows: 200K vs 128K tokens. Compare their real outputs side by side below.

Key Differences Between Claude Sonnet 4.5 and Grok 3 Thinking

Claude Sonnet 4.5 is made by anthropic while Grok 3 Thinking is from xai. Claude Sonnet 4.5 has a 200K token context window compared to Grok 3 Thinking's 128K.

Our Verdict
Claude Sonnet 4.5
Claude Sonnet 4.5
Grok 3 Thinking
Grok 3 Thinking

No community votes yet. On paper, these are closely matched - try both with your actual task to see which fits your workflow.

Too close to call
Writing DNA

Style Comparison

Similarity
97%

Claude Sonnet 4.5 uses 45.2x more emoji

Claude Sonnet 4.5
Grok 3 Thinking
64%Vocabulary46%
94wSentence Length19w
0.48Hedging1.11
4.9Bold3.3
8.0Lists2.6
0.45Emoji0.00
1.91Headings0.64
0.07Transitions0.25
Based on 20 + 6 text responses
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Claude Sonnet 4.5Grok 3 Thinking

279 AI models invented the same fake scientist.

We read every word. 250 models. 2.14 million words. This is what we found.

AI Hallucination Index 2026
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