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October 2026 review · same 50 texts

StealthGPT vs Phrasly

In the October 2026 HumanizerEval review, StealthGPT and Phrasly rewrote the same 50 English texts. StealthGPT cleared all 6 detectors on 17 of them; Phrasly on 0. The difference is mostly Pangram: on 42 samples StealthGPT passed it where Phrasly failed, and the reverse never happened. On ZeroGPT and Winston AI the two were close to even.

Per-sample agreement

Per-sample agreement, October 2026. Counts are out of the 50 shared samples, computed at the 50% human-score threshold. Margin counts the samples only one tool passed, higher count first.
DetectorPassed more oftenMarginBoth passedNeither passed
Pangram 4.1StealthGPT42 to 026
GPTZero 2026-10-07-baseStealthGPT25 to 1213
Originality.ai TurboStealthGPT13 to 3331
Originality.ai 5.0 model-5.0StealthGPT17 to 0033
ZeroGPT defaultStealthGPT4 to 3385
Winston AI 5.0StealthGPT5 to 4410
All 6 detectorsStealthGPT17 to 0033

Every count is computed from scores.csv at build time, not transcribed. “Neither passed” counts the texts that defeated both tools; on Pangram that was 6 of 50 here.

Quality and output discipline

Quality and output discipline, October 2026.
MeasureStealthGPTPhrasly
68%50%
82%70%
98%98%
86%84%
1.181.10
60
00
Super, quality mode, APIStandard model, API default (Phrasly Ultra not enabled on the account)
Websitestealthgpt.ai phrasly.ai

On per-sample quality scores, StealthGPT scored higher on 20 samples, Phrasly on 12, and the two tied on 18. Phrasly’s output was shorter on 35 of 50 samples; mean length ratios were 1.18 and 1.10, or 18% longer than the input and 10% longer than the input respectively.

Where StealthGPT outperforms Phrasly

StealthGPT

  • Pangram: passed 44 of 50 samples, against 2 for Phrasly.
  • GPTZero: passed 46 of 50 samples, against 22 for Phrasly.
  • Originality.ai Turbo: passed 46 of 50 samples, against 36 for Phrasly.
  • Originality.ai 5.0: passed 17 of 50 samples, against 0 for Phrasly.
  • ZeroGPT: passed 42 of 50 samples, against 41 for Phrasly.
  • Winston AI: passed 46 of 50 samples, against 45 for Phrasly.
  • Factual consistency: kept facts accurate in 68% of outputs, against 50% for Phrasly.
  • Naturalness: read fluently in 82% of outputs, against 70% for Phrasly.
  • Stance preservation: preserved the source’s stance in 86% of outputs, against 84% for Phrasly.

Phrasly

  • Pangram: failed 48 of 50 samples, 42 of which StealthGPT passed.
  • GPTZero: failed 28 of 50 samples, 25 of which StealthGPT passed.
  • Originality.ai Turbo: failed 14 of 50 samples, 13 of which StealthGPT passed.
  • Originality.ai 5.0: failed 50 of 50 samples, 17 of which StealthGPT passed.
  • ZeroGPT: failed 9 of 50 samples, 4 of which StealthGPT passed.
  • Winston AI: failed 5 of 50 samples, 5 of which StealthGPT passed.
  • Factual consistency: introduced factual errors in 50% of outputs.
  • Naturalness: had awkward or clunky phrasing in 30% of outputs.
  • Stance preservation: distorted the source’s stance in 16% of outputs.

StealthGPT vs Phrasly FAQ

Is StealthGPT better than Phrasly?

Yes. In the October 2026 HumanizerEval review, StealthGPT cleared all 6 detectors on 17 of the 50 shared samples and Phrasly on 0. On ZeroGPT and Winston AI the two were within 6 points of each other. Quality ran 20 samples to 12, with 18 ties.

Which humanizer is best for Pangram, StealthGPT or Phrasly?

StealthGPT. In October 2026, StealthGPT passed Pangram on 44 of the 50 shared samples and Phrasly on 2. On 42 samples StealthGPT passed where Phrasly failed; the reverse never happened. Both failed on 6.

Which humanizer changes the text less?

StealthGPT. It scored higher on per-sample quality on 20 of 50 samples, against 12. StealthGPT’s outputs averaged 1.18× the input length and passed factual consistency on 68%; Phrasly’s averaged 1.10× and passed on 50%. On stance preservation the split was 86% to 84%. Phrasly produced the shorter output on 35 of 50 samples.

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