OpenAI o3 vs Grok 3

Compare OpenAI o3 by OpenAI against Grok 3 by xAI, tested across 53 shared challenges. Updated April 2026.

Which is better, OpenAI o3 or Grok 3?

OpenAI o3 and Grok 3 are both competitive models. Compare their real outputs side by side below.

Key Differences Between OpenAI o3 and Grok 3

OpenAI o3 is made by openai while Grok 3 is from xai.

Our Verdict
OpenAI o3
OpenAI o3
Grok 3
Grok 3

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
96%

Grok 3 uses 3.9x more emoji

OpenAI o3
Grok 3
68%Vocabulary49%
14wSentence Length18w
0.26Hedging0.94
0.7Bold2.5
3.0Lists3.0
0.00Emoji0.04
0.38Headings0.65
0.12Transitions0.08
Based on 16 + 17 text responses
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Ask them anything yourself

OpenAI o3Grok 3

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
Free preview13 of 58 slides
FAQ

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