Gemini 1.5 Pro vs Z.ai: GLM 5.1
Compare Gemini 1.5 Pro by Google AI against Z.ai: GLM 5.1 by Z-ai, context windows of 1.0M vs 203K, tested across 18 shared challenges.
Our Verdict
Gemini 1.5 Pro
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.
Too close to call
API pricing
Cost per 1M tokens
Gemini 1.5 Pro
Input
$3.50
Output
$10.50
Z.ai: GLM 5.1
Input
$1.40
2.5× cheaper
Output
$4.40
2.4× cheaper
Z.ai: GLM 5.1 is cheaper on both — 2.5× input, 2.4× output
Writing DNA
Style Comparison
Similarity
59%
Z.ai: GLM 5.1 uses 5.4x more headings
Gemini 1.5 Pro
Z.ai: GLM 5.1
61%Vocabulary54%
15wSentence Length18w
0.80Hedging0.31
3.7Bold3.6
3.3Lists2.6
0.00Emoji0.00
0.08Headings0.43
0.09Transitions0.11
Based on 8 + 27 text responses
Research
What we learned reading every model
FAQ
