Z.ai: GLM 5.1 vs GPT-5.5
Compare Z.ai: GLM 5.1 by Z-ai against GPT-5.5 by OpenAI, in 19 community votes, z.ai: glm 5.1 wins 57% of head-to-head duels, context windows of 203K vs 1.1M, tested across 53 shared challenges.
Web Design: Z.ai: GLM 5.1 and GPT-5.5 are tied
Our Verdict
Z.ai: GLM 5.1Winner
GPT-5.5Runner-up
Z.ai: GLM 5.1 has the edge overall. In 19 blind votes, Z.ai: GLM 5.1 wins 57% of the time.
Z.ai: GLM 5.1 is 6.8x cheaper per token — worth considering if cost matters.
Slight edge
API pricing
Cost per 1M tokens
Z.ai: GLM 5.1
Input
$1.40
3.6× cheaper
Output
$4.40
6.8× cheaper
GPT-5.5
Input
$5.00
Output
$30.00
Z.ai: GLM 5.1 is cheaper on both — 3.6× input, 6.8× output
Writing DNA
Style Comparison
Similarity
37%
GPT-5.5 uses 3.9x more headings
Z.ai: GLM 5.1
GPT-5.5
54%Vocabulary58%
18wSentence Length18w
0.31Hedging0.74
3.6Bold2.9
2.6Lists5.1
0.00Emoji0.00
0.43Headings1.68
0.11Transitions0.03
Based on 27 + 26 text responses
Research
What we learned reading every model
FAQ
