GPT-5 vs xAI: Grok 4 Fast (free)
Compare GPT-5 by OpenAI against xAI: Grok 4 Fast (free) by xAI, context windows of 400K vs 2.0M, tested across 34 shared challenges.
Our Verdict
GPT-5
xAI: Grok 4 Fast (free)
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
GPT-5
Input
$1.25
Output
$10.00
xAI: Grok 4 Fast (free)
Input
$0.000
Output
$0.000
Writing DNA
Style Comparison
Similarity
56%
xAI: Grok 4 Fast (free) uses 10.0x more transitions
GPT-5
xAI: Grok 4 Fast (free)
65%Vocabulary65%
13wSentence Length13w
0.20Hedging0.56
0.2Bold1.4
4.6Lists2.5
0.00Emoji0.00
0.16Headings1.58
0.03Transitions0.28
Based on 16 + 14 text responses
Research
What we learned reading every model
FAQ
