GPT-5.3-Codex vs Grok 4.5
Compare GPT-5.3-Codex by OpenAI against Grok 4.5 by xAI, context windows of 400K vs 500K, tested across 53 shared challenges.
Our Verdict
GPT-5.3-Codex
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
GPT-5.3-Codex
Input
$1.75
1.1× cheaper
Output
$14.00
Grok 4.5
Input
$2.00
Output
$6.00
2.3× cheaper
GPT-5.3-Codex wins input (1.1× cheaper)·Grok 4.5 wins output (2.3× cheaper)
Writing DNA
Style Comparison
Similarity
47%
GPT-5.3-Codex uses 4.0x more headings
GPT-5.3-Codex
Grok 4.5
65%Vocabulary61%
23wSentence Length16w
0.51Hedging0.23
6.5Bold2.5
6.2Lists2.4
0.16Emoji0.09
1.90Headings0.48
0.03Transitions0.06
Based on 23 + 27 text responses
Research
What we learned reading every model
FAQ
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