o3 Mini vs Grok 3

Compare o3 Mini by OpenAI against Grok 3 by xAI, context windows of 64K vs 128K, tested across 53 shared challenges. Updated April 2026.

Which is better, o3 Mini or Grok 3?

o3 Mini and Grok 3 are both competitive models. Context windows: 64K vs 128K tokens. Compare their real outputs side by side below.

Key Differences Between o3 Mini and Grok 3

o3 Mini is made by openai while Grok 3 is from xai. o3 Mini has a 64K token context window compared to Grok 3's 128K.

Our Verdict
Grok 3
Grok 3
o3 Mini
o3 MiniRunner-up

No community votes yet. On paper, Grok 3 has the edge — bigger model tier, newer, bigger context window.

Slight edge
Writing DNA

Style Comparison

Similarity
99%

Grok 3 uses 3.9x more emoji

o3 Mini
Grok 3
65%Vocabulary49%
17wSentence Length18w
0.74Hedging0.94
3.9Bold2.5
1.7Lists3.0
0.00Emoji0.04
0.47Headings0.65
0.38Transitions0.08
Based on 12 + 17 text responses
vs

Ask them anything yourself

o3 MiniGrok 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

Common questions