Grok 4.1 Fast vs OpenAI o3
Compare Grok 4.1 Fast by xAI against OpenAI o3 by OpenAI, tested across 54 shared challenges. Updated June 2026.
Which is better, Grok 4.1 Fast or OpenAI o3?
Grok 4.1 Fast and OpenAI o3 are both competitive models. Compare their real outputs side by side below.
Key Differences Between Grok 4.1 Fast and OpenAI o3
Grok 4.1 Fast is made by xai while OpenAI o3 is from openai.
Our Verdict
Grok 4.1 Fast
OpenAI o3
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
API pricing
Cost per 1M tokens
Grok 4.1 Fast
Input
—
Output
—
OpenAI o3
Input
$10.00
Output
$40.00
Writing DNA
Style Comparison
Similarity
82%
Grok 4.1 Fast uses 6.7x more bold
Grok 4.1 Fast
OpenAI o3
67%Vocabulary68%
15wSentence Length14w
0.17Hedging0.26
4.7Bold0.7
3.7Lists3.0
0.00Emoji0.00
0.99Headings0.38
0.14Transitions0.12
Based on 24 + 16 text responses
Research
What we learned reading every model
FAQ
