Z.ai: GLM 5 vs GPT-5.5
Compare Z.ai: GLM 5 by Zhipu AI against GPT-5.5 by OpenAI, context windows of 203K vs 1.1M, tested across 53 shared challenges.
Our Verdict
GPT-5.5
Z.ai: GLM 5Runner-up
No community votes yet. On paper, GPT-5.5 has the edge — newer, bigger context window.
Z.ai: GLM 5 is 12x cheaper per token — worth considering if cost matters.
Too close to call
API pricing
Cost per 1M tokens
Z.ai: GLM 5
Input
$0.80
6.3× cheaper
Output
$2.56
12× cheaper
GPT-5.5
Input
$5.00
Output
$30.00
Z.ai: GLM 5 is cheaper on both — 6.3× input, 12× output
Writing DNA
Style Comparison
Similarity
47%
Z.ai: GLM 5 uses 5.2x more transitions
Z.ai: GLM 5
GPT-5.5
54%Vocabulary58%
17wSentence Length18w
0.37Hedging0.74
6.3Bold2.9
4.7Lists5.1
0.00Emoji0.00
0.60Headings1.68
0.18Transitions0.03
Based on 22 + 26 text responses
Research
What we learned reading every model
FAQ
