// AI detectors
GPTZero
Popular English-first AI detector for education, free to start.
official sources onlychecked 2026-10-26
01At a glance
| Official link | https://gptzero.me/ |
|---|---|
| Made by | GPTZero Inc. |
| Free? | Free to start; scans over 10,000 characters need a free account. Free monthly allowance: check the official pricing page. |
| Paid | Paid plans (monthly or annual); team plans include 500,000 words per member per month – see pricing. |
| Languages | Officially “fully supports” English, German, Portuguese, French and Spanish. |
| Files | Paste text or upload a file (accepted file types: check the official page). |
| Limits | 10,000 characters per scan without an account. |
| Best for | Teachers and students working in English. |
02How to use it
- Open gptzero.me, paste text or upload a file and click Scan.
- Create a free account for scans over 10,000 characters.
- Read sentence highlights as hints; discuss with the writer before drawing conclusions.
03Accuracy
Official claim: 99.9% accuracy; false-positive rate for ESL writing reduced to 1%.
Independent evaluations:
- Weber-Wulff et al. (2023), “Testing of detection tools for AI-generated text”, International Journal for Educational Integrity — 14 tools tested (12 public + Turnitin and PlagiarismCheck): all scored below 80% accuracy and only 5 above 70%; the authors conclude the tools are “neither accurate nor reliable”. False positives ranged from 0% (Turnitin) to 50% (GPTZero) on their test set; machine paraphrasing cut accuracy to 26%. English texts, tested in 2023 – tools have changed since.
- Liang et al. (2023), “GPT detectors are biased against non-native English writers”, Patterns — Several widely used GPT detectors “consistently misclassify non-native English writing samples as AI-generated, whereas native writing samples are accurately identified”; simple prompting can also bypass them. The authors caution against using detectors in evaluative or educational settings.
04FAQ
FAQ
Is GPTZero free?
You can start free; scans over 10,000 characters need a free account, and heavier use needs a paid plan.
Does GPTZero work for Chinese?
Its “fully supported” list is English, German, Portuguese, French and Spanish – Chinese is not on it. For Chinese text, Zhuque or CNKI AIGC check target Chinese.
Can GPTZero be wrong?
Yes – AI detection can misjudge. In the 2023 Weber-Wulff et al. study (tested in 2023), GPTZero had the highest false-positive rate of the tools tested. Vendors’ own figures are not independent evaluations.
05Official sources
Checked against these pages on 2026-10-26; the official page wins if anything differs.