GPT-5.3 Chat vs GPT-5.5
Compare GPT-5.3 Chat and GPT-5.5, both from OpenAI, context windows of 128K vs 1.1M, tested across 53 shared challenges.
Our Verdict
GPT-5.5
GPT-5.3 ChatRunner-up
No community votes yet. On paper, GPT-5.5 has the edge — bigger model tier, newer, bigger context window.
Slight edge
API pricing
Cost per 1M tokens
GPT-5.3 Chat
Input
$1.75
2.9× cheaper
Output
$14.00
2.1× cheaper
GPT-5.5
Input
$5.00
Output
$30.00
GPT-5.3 Chat is cheaper on both — 2.9× input, 2.1× output
Writing DNA
Style Comparison
Similarity
49%
GPT-5.5 uses 167.8x more headings
GPT-5.3 Chat
GPT-5.5
59%Vocabulary58%
26wSentence Length18w
0.84Hedging0.74
1.7Bold2.9
6.6Lists5.1
0.00Emoji0.00
0.00Headings1.68
0.25Transitions0.03
Based on 23 + 26 text responses
Research
What we learned reading every model
FAQ
