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The August 2026 results are in: WriteHuman holds #1, Undetectable AI falls to #8 on quality penalties.Read the full analysis →
HumanizerBench

StealthGPT vs Undetectable.ai

Head-to-head from the August 2026 cycle benchmark

Last tested
Sample size
33
Methodology
v1.2.0
Winner
61.49
overall
â–¼ 6
Bypass
86.0
Meaning
72.1
Readability
55.2
45.55
overall
â–¼ 4
Bypass
27.5
Meaning
62.9
Readability
70.9

Side-by-side metrics

Detector-level breakdown

Gold cell wins each row.

Detector StealthGPT Undetectable.ai
GPTZero 52.6 86.6
Winston AI 25.2 87.5
ZeroGPT 46.0 89.8
Copyleaks 24.2 65.3
Originality.ai 20.2 66.1

Minimum monthly pricing

StealthGPT
$25.50/mo
Free tier
No
Undetectable.ai
$19.00/mo
Free tier
Yes