🔍 AI detectors and plagiarism checkers
GPTZero
By GPTZero. Visit GPTZero
Desk research from the maker's own pages. Not yet tried by us. Checked 2026-10-24.
An AI-writing detector. A teacher or student pastes text or uploads a file and gets an estimate of how likely it was written by AI, with suspect sentences highlighted. It also offers a plagiarism check, a writing replay that records how a document was typed, grammar and feedback tools, and a Chrome extension. Teachers use it to screen essays, and some students use it to check their own work before turning it in.
Our take: A screening tool for adults, not proof of cheating; a family facing an accusation based on it should ask for the writing history and a conversation, not a number.
| Ages it suits | adults (teachers); markets to students |
|---|---|
| What its terms say about age | The site is intended for users at least 18 years old, and the privacy policy says it does not knowingly collect data from or market to anyone under 18, even though it has a page aimed at students. (terms) |
| Price | Free, with paid extras. Free for 10,000 words a month; Premium $12.99 a month and Professional $24.99 a month, billed yearly (USD, Oct 2026); team and API plans too. |
| Works on | Web, Chromebook |
| Account | A school account |
| Ads | Not stated |
| In-app purchases | Yes |
| The AI in it | Machine-learning models estimate the chance that text came from AI chatbots and highlight sentences that look machine-written. |
What's good
- Free tier for occasional checks
- Maker warns against using scores as a final verdict
- Writing replay can help a student show their process
- Sentence-level highlights explain the score
Watch for
- False positives, especially for English learners
- Terms say 18+ but it markets to students
- Accuracy figures are the maker's own
- A score can fuel unfair cheating accusations
Data and privacy
The privacy policy says third-party partners use tracking for analytics and tailored ads that may appear on GPTZero or other sites. It says it does not knowingly collect data from anyone under 18; no statement about training on submitted text was found. Read the privacy policy.
Does it work?
A 2023 Stanford study (Liang and others, published in Patterns) tested seven detectors including GPTZero and found they often misclassify essays by non-native English writers as AI-written. GPTZero claims 99.9% accuracy but says results should not be used to punish students.
In the Big Index
Alternatives to GPTZero
Desk researchFree, with paid extras
Course Hero
Course Hero, Inc. (Learneo, Inc.) · ages 13+ (aimed at college students)
Not a good fit for most teens; parents should treat it as an answer source that can undercut real learning.
Desk researchThrough schools
Turnitin (with AI writing detection)
Turnitin, LLC · ages about 11-18 and college (secondary and higher education)
Families cannot choose it, but should know how it works: an AI score is a reason for a conversation, and students should keep drafts and version history.
Where these facts come from
- https://gptzero.me/
- https://gptzero.me/pricing
- https://gptzero.me/terms-of-use.html
- https://gptzero.me/privacy-policy.html
- https://gptzero.me/students
- https://arxiv.org/abs/2304.02819
- https://arxiv.org/html/2304.02819v3
- Reviews on G2: https://www.g2.com/products/gptzero/reviews
Prices, terms and features change. Nobody paid to be listed, nothing here is an affiliate link, and Peabody never rates itself. Where we and the maker disagree, the maker's own pages are the ones to trust.