GPT-5.1 Chat vs xAI: Grok 4.5
Compare GPT-5.1 Chat by OpenAI against xAI: Grok 4.5 by xAI, context windows of 128K vs 500K, tested across 52 shared challenges.
Our Verdict
xAI: Grok 4.5
GPT-5.1 ChatRunner-up
No community votes yet. On paper, xAI: Grok 4.5 has the edge — newer, bigger context window.
Too close to call
API pricing
Cost per 1M tokens
GPT-5.1 Chat
Input
$1.25
1.6× cheaper
Output
$10.00
xAI: Grok 4.5
Input
$2.00
Output
$6.00
1.7× cheaper
GPT-5.1 Chat wins input (1.6× cheaper)·xAI: Grok 4.5 wins output (1.7× cheaper)
Writing DNA
Style Comparison
Similarity
63%
xAI: Grok 4.5 uses 9.0x more emoji
GPT-5.1 Chat
xAI: Grok 4.5
73%Vocabulary61%
18wSentence Length16w
0.45Hedging0.23
1.1Bold2.5
2.4Lists2.4
0.00Emoji0.09
0.00Headings0.48
0.06Transitions0.06
Based on 15 + 27 text responses
Research
What we learned reading every model
FAQ
