AI Humanizer Comparison: What the 10 Tool Leaderboard Shows

An AI humanizer comparison is only useful if you can see how each tool behaved on the same inputs. The September 2026 HumanizerEval leaderboard ranks 10 tools by mean strict bypass across five detectors, using the same 50 texts for everyone. The result is a wide spread, from 96.8% at the top to 23.6% at the bottom.

Here’s a plain language walkthrough of the full table, with the numbers that matter and a few cautions about how to read them.

Who Sits at the Top of the Table?

StealthGPT Super ranks first with a 96.8% mean bypass and passed all five detectors on 46 of 50 texts. WriteHuman is second at 92.7%, though it returned 49 outputs, so its rates are out of 49. It cleared all five detectors on 32 of those. The gap between first and second is four points, which is within the margin of error.

Grubby follows in third at 85.6%, with 18 of 50 texts clearing every detector. Then comes a tie at 84.0% between Rephrasy and Undetectable.ai, separated by the tiebreak: Rephrasy cleared all five on 20 texts and Undetectable.ai on 15. So the leaders are clear, and the middle starts to bunch together.

What Does the Middle and Bottom Look Like?

RewriteAI is sixth at 77.2%, having cleared all five detectors on 13 texts. HIX Bypass and Humbot both land at 66.4%, with HIX ahead because it cleared all five on 1 text and Humbot on none. BypassGPT follows at 64.4% with zero full clears, and Ryne sits last at 23.6%.

That ordering hides a pattern. Four tools cleared every detector on at least 13 texts, while the bottom four rarely or never did. This AI humanizer comparison therefore splits into a top group, a mid group and a group that struggles on the hardest detector, which is Pangram.

Why Is Pangram the Deciding Column?

Look at the Pangram column. StealthGPT Super passed 92%, WriteHuman 65%, Rephrasy 46%, Grubby 36%, Undetectable.ai 32% and RewriteAI 28%. Ryne passed 22%, HIX Bypass 2%, and Humbot and BypassGPT 0%. The average across tools was only 32%.

Compare that with ZeroGPT, where the average was 95% and seven tools tied at 100%. On Winston AI, five tools tied at 100%. In other words, ZeroGPT and Winston AI separate tools very little, while Pangram sorts them sharply. That’s why the ranking order tracks the Pangram column more closely than any other.

How Does Quality Change the Picture?

Quality is reported separately and never enters the ranking. StealthGPT Super had the best mean quality pass rate at 83.5%, then Ryne at 79.0% and Grubby at 77.5%. RewriteAI scored 72.0%, WriteHuman 58.7%, Undetectable.ai 56.5%, Rephrasy 54.5%, BypassGPT 49.0%, Humbot 47.5% and HIX Bypass 46.5%.

Notice who moved. Ryne ranks last on bypass but second on quality, while WriteHuman ranks second on bypass but sits in the lower half on quality. If you only read the rank, you’d miss both facts. This is why a good AI humanizer comparison should keep the two scores apart and let you decide how to weigh them.

What Are the Limits of This Table?

The sample is 50 texts drawn from production outputs, so a 95% confidence interval is about plus or minus 14 points. Small gaps are noise. The test also reflects one run on September 30, 2026, with detector settings recorded at that time, and a silent detector update could shift results later.

Provenance matters too. The public data repo sits under the StealthGPT Labs account, and StealthGPT Super ranks first. The CSV is public and a script recomputes every aggregate, so you can check the arithmetic. Still, treat the table as strong evidence about these 50 texts rather than a final verdict on any tool.

• Read the Pangram column first

• Check quality next

• Treat gaps under 14 points as noise

• Verify any number you plan to rely on

How Do You Compare Top AI Humanizer Services With This Data?

Use the table as a filter, not a decision. If you want to compare top AI humanizer services for your own work, shortlist the two or three that perform well on your audience’s detector, then check their quality columns and length ratios. The leaderboard does the narrowing, and your own samples make the final call.

Then test. Take one real document, run it through each shortlisted tool with the same settings and read the outputs against the original. Look for changed numbers, flattened voice and added length. A short test like that tells you whether a tool fits your content, which no general table can answer on its own.

Conclusion

The leaderboard shows a clear top group, a bunched middle and a struggling bottom, with Pangram doing most of the sorting. Quality tells a different story from bypass, and the margin of error keeps small gaps in perspective. Use it to shortlist, then verify.

FAQs

Who ranks first in the September 2026 leaderboard?
StealthGPT Super, with a 96.8% mean strict bypass across five detectors.

How was the Rephrasy and Undetectable.ai tie broken?
Both had an 84.0% mean. Rephrasy ranks higher because it cleared all five detectors on 20 texts versus 15.

Which detector separates tools most sharply?
Pangram. The average tool passed it on 32% of texts, compared with 95% on ZeroGPT.

Is quality part of the ranking?
No. Quality pass rates are reported separately and never enter the rank.