GPT-5.5 vs xAI: Grok 4.5
Compare GPT-5.5 by OpenAI against xAI: Grok 4.5 by xAI, context windows of 1.1M vs 500K, tested across 54 shared challenges.
Our Verdict
GPT-5.5
xAI: Grok 4.5Runner-up
No community votes yet. On paper, GPT-5.5 has the edge — bigger model tier, bigger context window.
xAI: Grok 4.5 is 5.0x cheaper per token — worth considering if cost matters.
Too close to call
API pricing
Cost per 1M tokens
GPT-5.5
Input
$5.00
Output
$30.00
xAI: Grok 4.5
Input
$2.00
2.5× cheaper
Output
$6.00
5.0× cheaper
xAI: Grok 4.5 is cheaper on both — 2.5× input, 5.0× output
Writing DNA
Style Comparison
Similarity
50%
xAI: Grok 4.5 uses 9.0x more emoji
GPT-5.5
xAI: Grok 4.5
58%Vocabulary61%
18wSentence Length16w
0.74Hedging0.23
2.9Bold2.5
5.1Lists2.4
0.00Emoji0.09
1.68Headings0.48
0.03Transitions0.06
Based on 26 + 27 text responses
Research
What we learned reading every model
FAQ
