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The September 2026 results are in: WriteHuman holds #1, and newcomer SupWriter debuts at #5.Read the full analysis →
HumanizerBench

Head to head · September 2026 cycle

AI Humanize io vs StealthGPT

AI Humanize io finished 7.8 points ahead of StealthGPT in the September 2026 cycle, 72.94 to 65.10, ranking #4 against #9 in a field of 14. AI Humanize io scored higher on 3 of 5 detectors and 7 of 7 writing categories. StealthGPT came out ahead on GPTZero (77.4 vs 55.8), Copyleaks (81.8 vs 60.6) and readability (70.9 vs 58.4). The bypass-rate gap, 81.5 to 79.6, sits inside both tools' 95% confidence intervals, so treat bypass as a draw.

72.94 /100
overall score
#4 /14
rank ▲ 2
+7.84
← AI Humanize io leads
Detectors
3 2
Categories
7 0
Components
4 1
65.10 /100
overall score
#9 /14
rank ▲ 3
Last tested
Prompts
33
Methodology
v1.2.0

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 →

Bypass rate CIs overlap AI Humanize io by 1.9
81.5 79.6
Meaning preservation AI Humanize io by 13.8
73.2 59.4
Readability StealthGPT by 12.5
58.4 70.9
Consistency AI Humanize io by 6.1
69.2 63.1
Penalties fewer is better AI Humanize io by 4.0
−1.0 −5.0

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. AI Humanize io took 3 of 5.

GPTZero StealthGPT by 21.6
55.8 77.4
Originality.ai AI Humanize io by 3.8
93.3 89.5
Copyleaks StealthGPT by 21.2
60.6 81.8
Winston AI AI Humanize io by 12.4
79.0 66.6
ZeroGPT AI Humanize io by 6.1
75.0 68.9

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 →

Academic Essay Application Essay Blog Post Business Email Marketing Copy Discussion Board News Article Academic Essay: AI Humanize io 80.3 · StealthGPT 79.4 Application Essay: AI Humanize io 68.0 · StealthGPT 60.3 Blog Post: AI Humanize io 80.9 · StealthGPT 60.7 Business Email: AI Humanize io 46.2 · StealthGPT 42.7 Marketing Copy: AI Humanize io 82.4 · StealthGPT 73.1 Discussion Board: AI Humanize io 62.5 · StealthGPT 60.1 News Article: AI Humanize io 71.8 · StealthGPT 64.9
AI Humanize io StealthGPT Outer ring = 100
Academic Essay 6 prompts AI Humanize io by 0.9
80.3 79.4
Application Essay 6 prompts AI Humanize io by 7.7
68.0 60.3
Blog Post 6 prompts AI Humanize io by 20.2
80.9 60.7
Business Email 3 prompts AI Humanize io by 3.5
46.2 42.7
Marketing Copy 6 prompts AI Humanize io by 9.2
82.4 73.1
Discussion Board 3 prompts AI Humanize io by 2.4
62.5 60.1
News Article 3 prompts AI Humanize io by 6.9
71.8 64.9

Head-to-head history

Overall score in every cycle both tools were tested. AI Humanize io has finished ahead in 3 of 4 shared cycles.

40 50 60 70 80 June 2026 July 2026 August 2026 September 2026 June 2026: StealthGPT 71.47 (#7) June 2026: AI Humanize io 72.95 (#6) July 2026: StealthGPT 61.52 (#8) July 2026: AI Humanize io 59.66 (#10) August 2026: StealthGPT 45.55 (#12) August 2026: AI Humanize io 64.57 (#6) September 2026: StealthGPT 65.10 (#9) September 2026: AI Humanize io 72.94 (#4) 72.9 65.1
AI Humanize io StealthGPT
Cycle AI Humanize io StealthGPT Margin
September 2026 72.94 #4 65.10 #9 ← 7.8
August 2026 64.57 #6 45.55 #12 ← 19.0
July 2026 59.66 #10 61.52 #8 → 1.9
June 2026 72.95 #6 71.47 #7 ← 1.5

Where each one wins

Every measure above that one tool won outright, largest margin first within each group.

AI Humanize io

14 wins
  • Penalties Score −1.0 vs −5.0
  • Meaning preservation Score 73.2 vs 59.4
  • Consistency Score 69.2 vs 63.1
  • Bypass rate Score 81.5 vs 79.6
  • Winston AI Detector 79.0 vs 66.6
  • ZeroGPT Detector 75.0 vs 68.9
  • Originality.ai Detector 93.3 vs 89.5
  • Blog Post Category 80.9 vs 60.7
  • Marketing Copy Category 82.4 vs 73.1
  • Application Essay Category 68.0 vs 60.3
  • and 4 more

StealthGPT

3 wins
  • Readability Score 70.9 vs 58.4
  • GPTZero Detector 77.4 vs 55.8
  • Copyleaks Detector 81.8 vs 60.6

Questions people ask

Is AI Humanize io better than StealthGPT?

AI Humanize io finished 7.8 points ahead of StealthGPT in the September 2026 cycle, 72.94 to 65.10, ranking #4 against #9 in a field of 14. AI Humanize io scored higher on 3 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, AI Humanize io or StealthGPT?

AI Humanize io posted the higher bypass rate, 81.5 vs 79.6, and scored higher on 3 of 5 detectors. AI Humanize io led on Originality.ai, Winston AI and ZeroGPT; StealthGPT led on GPTZero and Copyleaks. The overall bypass gap is inside both 95% confidence intervals, so it is not a reliable difference.

Do AI Humanize io and StealthGPT keep the original meaning?

AI Humanize io preserved meaning better, 73.2 vs 59.4 on our 0–100 similarity scale. On readability, StealthGPT rated higher, 70.9 vs 58.4. Penalties this cycle: AI Humanize io −1.0, StealthGPT −5.0.