GPT-4.5 vs GPT-5.5
Compare GPT-4.5 and GPT-5.5, both from OpenAI, context windows of 128K vs 1.1M, tested across 24 shared challenges.
Our Verdict
GPT-5.5
GPT-4.5Runner-up
No community votes yet. On paper, GPT-5.5 has the edge — newer, bigger context window.
GPT-5.5 is 5.0x cheaper per token — worth considering if cost matters.
Too close to call
API pricing
Cost per 1M tokens
GPT-4.5
Input
$75.00
Output
$150.00
GPT-5.5
Input
$5.00
15× cheaper
Output
$30.00
5.0× cheaper
GPT-5.5 is cheaper on both — 15× input, 5.0× output
Writing DNA
Style Comparison
Similarity
50%
GPT-4.5 uses 15.6x more transitions
GPT-4.5
GPT-5.5
63%Vocabulary58%
16wSentence Length18w
0.57Hedging0.74
4.7Bold2.9
6.4Lists5.1
0.00Emoji0.00
1.30Headings1.68
0.54Transitions0.03
Based on 11 + 26 text responses
Research
What we learned reading every model
FAQ
Common questions
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