OpenAI: GPT-5.6 Luna Pro vs Grok 4.20 Beta
Compare OpenAI: GPT-5.6 Luna Pro by OpenAI against Grok 4.20 Beta by xAI, context windows of 1.1M vs 2.0M, tested across 53 shared challenges.
Our Verdict
Grok 4.20 Beta
OpenAI: GPT-5.6 Luna ProRunner-up
No community votes yet. On paper, Grok 4.20 Beta has the edge — bigger model tier, bigger context window.
Too close to call
API pricing
Cost per 1M tokens
OpenAI: GPT-5.6 Luna Pro
Input
$1.00
2.0× cheaper
Output
$6.00
Grok 4.20 Beta
Input
$2.00
Output
$6.00
Writing DNA
Style Comparison
Similarity
62%
OpenAI: GPT-5.6 Luna Pro uses 53.7x more emoji
OpenAI: GPT-5.6 Luna Pro
Grok 4.20 Beta
58%Vocabulary57%
18wSentence Length20w
0.81Hedging0.35
2.9Bold4.2
5.1Lists3.7
0.54Emoji0.00
1.10Headings0.62
0.09Transitions0.14
Based on 27 + 23 text responses
Research
What we learned reading every model
FAQ
