GPTZero
Verified Oct 15, 2026 ActiveEstimates whether text was machine-written and flags the sentences
Listed on EffectHub ·
Pricing
- Pricing model
- Freemium
- Paid options from
- $12.99/mo
- Billing
- Monthly
Free covers 10,000 words a month. Premium is $23.99 a month, or $155.88 a year ($12.99 a month) billed annually, for 300,000 words; Professional is $45.99 a month or $299.88 a year for 500,000 words plus overage. The API starts at $45 a month for 300,000 words. Prices read from the plan data the pricing page loads, as the page renders them client-side.
Use tool ↗About GPTZero
GPTZero scores a document for machine authorship and highlights the individual sentences that drove the score, which is the part schools and publishers act on rather than the headline percentage. Premium raises the allowance to 300,000 words a month and adds multilingual detection, downloadable reports and highlights in the Chrome extension; Professional adds batch scans of up to 250 files, page-by-page scanning and LMS integration. A separate developer API is sold by monthly word volume. The free tier is metered in words, so one long thesis can use up most of a month.
- Platforms
- Web · API · Chrome extension
- API
- Yes
- Last verified
- Oct 15, 2026
Verified sources
- Pricing page offers Annual (save 45%) and Monthly billing; its plan data lists Free at 10,000 words a month, Premium $23.99 a month or $155.88 a year, Professional $45.99 a month or $299.88 a year (15 October 2026)gptzero.me ↗
- Professional team plan priced per seat with 500,000 words per member a month and a minimum of two seats; separate developer API from $45 a month for 300,000 words (15 October 2026)gptzero.me ↗
- Home page footer: products include AI Detector, Plagiarism Check, Writing Replay and a Chrome extension, copyright 2023 to 2026 GPTZero (15 October 2026)gptzero.me ↗
Is GPTZero legit?
We don’t label tools safe or unsafe. Below are the records we checked ourselves, each with the date we read it.
- TLS certificate
- Issued by Google Trust Services, valid until Jan 1, 2027Seen in our own connection to the site on Oct 15, 2026
- Last checked
- Oct 15, 2026The site answered
- On the market since
- 2023The vendor's own material, read by us
- Operated by
- GPTZero, United StatesOur research, card verified Oct 15, 2026
Pros & cons of GPTZero
One of the detectors schools most often adopt, and the sentence-level highlighting is what makes a result usable in a conversation with a student rather than a bare percentage. No detector is evidence of authorship, though, and the cheap Essential tier is gone from the pricing page, so paid use now starts at Premium.
Pros
- Sentence-level highlighting shows what drove the score instead of a bare percentage
- Batch uploads and a developer API make it usable inside an existing review workflow
- Free tier is generous enough to evaluate properly before paying
Cons
- The Essential tier has been dropped, so the cheapest paid plan is Premium at $12.99 a month on annual billing or $23.99 month to month
- The developer API is priced separately from the writing plans, starting at $45 a month
- Word-metered quotas punish long documents disproportionately
- Detection accuracy remains contested and the tool cannot prove authorship
Best for
- Schools and universities that need a defensible second opinion, not a verdict
- Editors screening freelance submissions at volume
- Teams wanting provenance reporting on documents they commissioned
Not for
- Anyone treating a score as proof of misconduct
- Non-native English writers being screened, where false positives are a documented pattern
Watch out: Quotas are counted in words and each scan has a character cap (10,000 characters on Free, 50,000 on Premium), so a full dissertation has to be split, and the free monthly allowance of 10,000 words is gone after one long paper.
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GPTZero head-to-head
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