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Detector review · GPTZero, Inc.

GPTZero Review

One of the first and best-known AI detectors, launched in January 2023 by Princeton student Edward Tian. It is popular in education and also offers authorship-tracking tools that show editing history.

Our take

A solid, accessible detector for screening, especially on unedited text. Not a tool to base a penalty on by itself.

At a glance

  • Best for: Teachers and students who want a widely known detector with sentence highlighting
  • Free option: Free plan with a monthly word allowance (10,000 words a month as of late 2025)
  • Website: gptzero.me

Main features

  • Overall score with sentence-level highlighting
  • Writing-history and authorship tracking tools
  • Education-focused features and integrations
  • API for developers

Strengths

  • Easy to use with a usable free plan
  • Explains results at the sentence level
  • Performed well on unedited AI text in a 2025 University of Chicago study

Limits and concerns

  • The same study found it missed a large share of AI text that had been run through a humanizer tool
  • Like other detectors in 2023, it was reported to flag the U.S. Constitution as AI-written
  • Critics have raised concerns about false accusations in classrooms
Remember: no detector score is proof that someone used AI. How accurate are AI detectors?

Sources

Last reviewed October 2026. Features and free limits change often; check the product’s site for current details. We have no affiliate relationship with any product reviewed here.