Head to head · September 2026 cycle
Penlify vs StealthGPT
StealthGPT finished 28.5 points ahead of Penlify in the September 2026 cycle, 65.10 to 36.57, ranking #9 against #14 in a field of 14. StealthGPT scored higher on 5 of 5 detectors and 7 of 7 writing categories. Penlify came out ahead on consistency across categories (100.0 vs 63.1), meaning preservation (62.7 vs 59.4) and readability (71.8 vs 70.9).
- Detectors
- 0 – 5
- Categories
- 0 – 7
- Components
- 3 – 1 (1 tie)
Score components
What the overall score is made of: bypass rate weighs 42%, meaning preservation 32%, readability 16%, consistency across categories 10%. Output-quality penalties come off the total. How scoring works →
CIs overlap marks a gap that sits inside both tools' published 95% confidence intervals for that component; it may not survive another cycle.
Detector by detector
Share of each tool's outputs that a detector classified as human-written. StealthGPT took 5 of 5.
Writing categories
Category score per writing context: bypass credit only for real rewrites, blended with the category's own meaning preservation and readability. Small categories swing; the prompt count is shown on each row. How category scores work →
Where each one wins
Every measure above that one tool won outright, largest margin first within each group.
Penlify
3 wins- Consistency Score 100.0 vs 63.1
- Meaning preservation Score 62.7 vs 59.4
- Readability Score 71.8 vs 70.9
StealthGPT
13 wins- Bypass rate Score 79.6 vs 0.0
- Originality.ai Detector 89.5 vs 0.0
- Copyleaks Detector 81.8 vs 0.0
- GPTZero Detector 77.4 vs 0.0
- Winston AI Detector 66.6 vs 0.4
- ZeroGPT Detector 68.9 vs 43.0
- Academic Essay Category 79.4 vs 27.0
- Marketing Copy Category 73.1 vs 38.8
- News Article Category 64.9 vs 36.6
- Discussion Board Category 60.1 vs 32.1
- and 3 more
Questions people ask
Is Penlify better than StealthGPT?
StealthGPT finished 28.5 points ahead of Penlify in the September 2026 cycle, 65.10 to 36.57, ranking #9 against #14 in a field of 14. StealthGPT scored higher on 5 of 5 detectors and 7 of 7 writing categories. Both tools ran the same 33 prompts, scored by the same 5 detectors, under methodology v1.2.0; every input, output and verdict is published.
Which bypasses AI detectors better, Penlify or StealthGPT?
StealthGPT posted the higher bypass rate, 79.6 vs 0.0, and scored higher on 5 of 5 detectors. StealthGPT led on GPTZero, Originality.ai, Copyleaks, Winston AI and ZeroGPT.
Do Penlify and StealthGPT keep the original meaning?
Penlify preserved meaning better, 62.7 vs 59.4 on our 0–100 similarity scale, though the confidence intervals overlap. On readability, Penlify rated higher, 71.8 vs 70.9. Penalties this cycle: Penlify −5.0, StealthGPT −5.0.