Claude 3 Opus vs xAI: Grok 4

Compare Claude 3 Opus by Anthropic against xAI: Grok 4 by xAI, context windows of 200K vs 256K, tested across 10 shared challenges. Updated April 2026.

Which is better, Claude 3 Opus or xAI: Grok 4?

Claude 3 Opus and xAI: Grok 4 are both competitive models. Claude 3 Opus costs $15/M input tokens vs $3/M for xAI: Grok 4. Context windows: 200K vs 256K tokens. Compare their real outputs side by side below.

Key Differences Between Claude 3 Opus and xAI: Grok 4

Claude 3 Opus is made by anthropic while xAI: Grok 4 is from xai. Claude 3 Opus has a 200K token context window compared to xAI: Grok 4's 256K. On pricing, Claude 3 Opus costs $15/M input tokens vs $3/M for xAI: Grok 4.

Our Verdict
Claude 3 Opus
Claude 3 Opus
xAI: Grok 4
xAI: Grok 4

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

xAI: Grok 4 is 5.0x cheaper per token — worth considering if cost matters.

Too close to call
Writing DNA

Style Comparison

Similarity
94%

xAI: Grok 4 uses 267.9x more bold

Claude 3 Opus
xAI: Grok 4
54%Vocabulary53%
14wSentence Length18w
0.48Hedging0.67
0.0Bold2.7
3.0Lists2.7
0.00Emoji0.07
0.00Headings0.86
0.06Transitions0.04
Based on 3 + 21 text responses
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Claude 3 OpusxAI: Grok 4

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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