The short answer
GPTZero and ZeroGPT are separate AI detectors from separate companies. Both give a score and highlight sentences. GPTZero describes more school connections and a monthly free allowance. ZeroGPT shows a large free box on its home page. Neither is proved more accurate, and they can disagree on the same text.
Comparison table
| GPTZero | ZeroGPT | |
|---|---|---|
| Free allowance | 10,000 words a month, up to 10,000 characters a scan | The home page box showed a 15,000-character counter |
| Suggested length | No minimum stated. It says accuracy rises with more text. | At least 150 to 200 words. 500 to 1,000 or more improves stability. |
| Result | Human, mixed or AI, with a confidence level and highlights | A percentage gauge, with AI sentences highlighted |
| Languages | English and more than 20 others | “All available languages”. No list on the pages we read. |
| Connections | Chrome, Google Docs, Google Classroom, Canvas, Zapier and an API | An API, which its FAQ said can connect to an LMS |
| Plagiarism check | Yes. Its pages differ on whether the free plan includes it. | Yes, after sign-up |
| Paid price | The pricing page showed no readable individual price | The pricing page showed no readable paid price |
Limits change, so check the maker’s page on the day you use it.
Accuracy claims
- GPTZero says it detects 95.7% of AI texts on the RAID benchmark while flagging 1% of human texts, and over 99% with older models removed.
- ZeroGPT says 98.4% detection accuracy and a false positive rate under 1%. Its FAQ refers to internal evaluations.
These numbers come from different tests, so a higher one does not mean a better tool. GPTZero’s post also says ZeroGPT is less accurate. That is one rival writing about another, and it gives no ZeroGPT figure.
Both were among the 14 tools in Weber-Wulff et al. (2023), where every tool scored under 80% overall. We could not read a separate figure for ZeroGPT, and both tools have changed since. For more, see is GPTZero accurate? and is ZeroGPT accurate?
Which one fits
- You want to paste one text quickly. Compare the free limits above with your word count.
- You teach and use Canvas or Google Classroom. Check GPTZero’s connections, and check what your school already licenses.
- You got a different score from each. That is normal. It is why no single score is proof. See AI detector false positives.
- You also need a plagiarism check. Our Plagiarism Checker Plus runs both on one account, with a free account of 3,000 words a month. It has no database of other students’ papers, and we publish no accuracy figure.
Sources
- GPTZero: comparison post (read 1 November 2026), plans (1 November 2026) and home page (17 October and 1 November 2026).
- ZeroGPT: home page and FAQ (read 1 November 2026), and the LMS and pricing notes from our reading on 10 October 2026.