xAI: Grok 4 Fast (free) vs xAI: Grok 4.5
Compare xAI: Grok 4 Fast (free) and xAI: Grok 4.5, both from xAI, context windows of 2.0M vs 500K, tested across 34 shared challenges.
Our Verdict
xAI: Grok 4 Fast (free)
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
xAI: Grok 4 Fast (free)
Input
$0.000
Output
$0.000
xAI: Grok 4.5
Input
$2.00
Output
$6.00
Writing DNA
Style Comparison
Similarity
65%
xAI: Grok 4.5 uses 9.0x more emoji
xAI: Grok 4 Fast (free)
xAI: Grok 4.5
65%Vocabulary61%
13wSentence Length16w
0.56Hedging0.23
1.4Bold2.5
2.5Lists2.4
0.00Emoji0.09
1.58Headings0.48
0.28Transitions0.06
Based on 14 + 27 text responses
Research
What we learned reading every model
FAQ
