OpenAI: GPT-5.6 Luna vs xAI: Grok 4.5
Compare OpenAI: GPT-5.6 Luna by OpenAI against xAI: Grok 4.5 by xAI, context windows of 1.1M vs 500K, tested across 54 shared challenges.
Our Verdict
OpenAI: GPT-5.6 Luna
xAI: Grok 4.5
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
OpenAI: GPT-5.6 Luna
Input
$1.00
2.0× cheaper
Output
$6.00
xAI: Grok 4.5
Input
$2.00
Output
$6.00
Writing DNA
Style Comparison
Similarity
57%
xAI: Grok 4.5 uses 9.0x more emoji
OpenAI: GPT-5.6 Luna
xAI: Grok 4.5
59%Vocabulary61%
19wSentence Length16w
0.84Hedging0.23
2.7Bold2.5
4.5Lists2.4
0.00Emoji0.09
1.20Headings0.48
0.10Transitions0.06
Based on 27 + 27 text responses
Research
What we learned reading every model
FAQ
