Z.AI: GLM 4.5 Air vs Z.ai: GLM 5.1
Compare Z.AI: GLM 4.5 Air by Zhipu AI against Z.ai: GLM 5.1 by Z-ai, context windows of 128K vs 203K, tested across 53 shared challenges.
Our Verdict
Z.AI: GLM 4.5 Air
Z.ai: GLM 5.1
No community votes yet. On paper, these are closely matched - try both with your actual task to see which fits your workflow.
Z.AI: GLM 4.5 Air is 4.0x cheaper per token — worth considering if cost matters.
Too close to call
API pricing
Cost per 1M tokens
Z.AI: GLM 4.5 Air
Input
$0.20
7.0× cheaper
Output
$1.10
4.0× cheaper
Z.ai: GLM 5.1
Input
$1.40
Output
$4.40
Z.AI: GLM 4.5 Air is cheaper on both — 7.0× input, 4.0× output
Writing DNA
Style Comparison
Similarity
60%
Z.AI: GLM 4.5 Air uses 9.9x more emoji
Z.AI: GLM 4.5 Air
Z.ai: GLM 5.1
48%Vocabulary54%
16wSentence Length18w
0.40Hedging0.31
5.4Bold3.6
4.8Lists2.6
0.10Emoji0.00
0.75Headings0.43
0.12Transitions0.11
Based on 15 + 27 text responses
Research
What we learned reading every model
FAQ
