AI Humanizer Benchmark

October 2026 prompt evidence

This cycle used 33 prompts, each with its own AI-written input text. All 11 ranked humanizers rewrote every input text, and 7 commercial AI detectors scored each rewrite. Pick a row below to see a prompt's input text, each tool's rewrite, and every detector's score.

Cycle
33
Prompts
11
Tools ranked
363
Humanizer outputs
2541
Detector verdicts
PromptCategoryInput modelInput wordsPassedFailedHardest
01Argumentative essayAcademic essayGemini 2.5 Flash23289GPTZero
02Lit reviewAcademic essayClaude Sonnet 532587GPTZero
03Cover letterApplication essayGPT-5.6 Luna245211Copyleaks
04Personal statementApplication essayGemini 3.5 Flash26595GPTZero
05How-to blogBlog postClaude Haiku 4.528457GPTZero
06Listicle blogBlog postGPT-5.6 Terra336310Winston AI
07Business emailBusiness emailGemini 2.5 Flash195210Copyleaks
08Landing copyMarketing copyClaude Sonnet 528349GPTZero
09Product descriptionMarketing copyGPT-5.6 Luna21177ZeroGPT
10Discussion postDiscussion boardGemini 3.5 Flash24587GPTZero
11News articleNews articleClaude Haiku 4.530378GPTZero
12Argumentative essayAcademic essayGPT-5.6 Terra32796GPTZero
13Lit reviewAcademic essayGemini 2.5 Flash25695GPTZero
14Cover letterApplication essayClaude Sonnet 5321310Copyleaks
15Personal statementApplication essayGPT-5.6 Luna28285GPTZero
16How-to blogBlog postGemini 3.5 Flash29787Copyleaks
17Listicle blogBlog postClaude Haiku 4.528759GPTZero
18Business emailBusiness emailGPT-5.6 Terra258111GPTZero
19Landing copyMarketing copyGemini 2.5 Flash30049GPTZero
20Product descriptionMarketing copyClaude Sonnet 519977GPTZero
21Discussion postDiscussion boardGPT-5.6 Luna26578GPTZero
22News articleNews articleGemini 3.5 Flash30285GPTZero
23Argumentative essayAcademic essayClaude Haiku 4.530596GPTZero
24Lit reviewAcademic essayGPT-5.6 Terra35484GPTZero
25Cover letterApplication essayGemini 2.5 Flash281210QuillBot
26Personal statementApplication essayClaude Sonnet 531988GPTZero
27How-to blogBlog postGPT-5.6 Luna27759GPTZero
28Listicle blogBlog postGemini 3.5 Flash33477GPTZero
29Business emailBusiness emailClaude Haiku 4.5229210Copyleaks
30Landing copyMarketing copyGPT-5.6 Terra27977GPTZero
31Product descriptionMarketing copyGemini 2.5 Flash12977Winston AI
32Discussion postDiscussion boardClaude Sonnet 524795GPTZero
33News articleNews articleGPT-5.6 Luna30988GPTZero

How to read the columns. A tool counts as “Passed” when 6 or more of the 7 detectors gave its rewrite a human-likelihood score of 0.50 or higher. It counts as “Failed” when any detector that returned a score put it below 0.50. So one tool can count in both columns. “Hardest” is the detector that caught the most tools on that prompt. If several are tied, only one is shown.

How to read these scores

Each detector's result is converted to a human-likelihood score between 0 and 1. A score of 0 means the detector is sure the text is AI. A score of 1 means it is sure the text is human. Dots are green at 0.50 or above and red below. Hover a dot to see its exact score. The 0.50 cut-off only sets the dot colors. A tool's bypass rate on the leaderboard takes the median of the 7 detector scores for each test, then averages those medians. That gives a continuous number, so it will not match the share of green dots. The same goes for each per-detector rate. It is the average of that detector's scores (the number detector pages rank by), not a count of green dots.

Raw data

Each ranked tool has its own JSONL file for this cycle, with one row per prompt. A row holds the prompt, its input text, the tool's rewrite, its meaning preservation and readability scores, and the run status. Scores from the 7 detectors are in separate files, one per detector, in the cycle's GitHub folder.

UndetectedGPT
33 rows · .jsonl
HIX Bypass
33 rows · .jsonl
GPTinf
33 rows · .jsonl
SmartHumanizer
33 rows · .jsonl
AI Humanize
33 rows · .jsonl
SuperHumanizer
33 rows · .jsonl
WriteHuman
33 rows · .jsonl
CleverHumanizer
33 rows · .jsonl
StealthGPT
33 rows · .jsonl
ReHumanize
33 rows · .jsonl
Undetectable AI
33 rows · .jsonl