Z.AI: GLM 4.5 Air vs GPT-5.1
Compare Z.AI: GLM 4.5 Air by Zhipu AI against GPT-5.1 by OpenAI, context windows of 128K vs 400K, tested across 51 shared challenges.
Our Verdict
GPT-5.1
Z.AI: GLM 4.5 AirRunner-up
No community votes yet. On paper, GPT-5.1 has the edge — bigger model tier, newer, bigger context window.
Z.AI: GLM 4.5 Air is 9.1x cheaper per token — worth considering if cost matters.
Slight edge
API pricing
Cost per 1M tokens
Z.AI: GLM 4.5 Air
Input
$0.20
6.3× cheaper
Output
$1.10
9.1× cheaper
GPT-5.1
Input
$1.25
Output
$10.00
Z.AI: GLM 4.5 Air is cheaper on both — 6.3× input, 9.1× output
Writing DNA
Style Comparison
Similarity
47%
Z.AI: GLM 4.5 Air uses 9.9x more emoji
Z.AI: GLM 4.5 Air
GPT-5.1
48%Vocabulary62%
16wSentence Length19w
0.40Hedging0.29
5.4Bold3.5
4.8Lists7.2
0.10Emoji0.00
0.75Headings0.61
0.12Transitions0.03
Based on 15 + 14 text responses
Research
What we learned reading every model
FAQ
