Comparison updated 2026-10-10

GPTZero or ProofAI? Monthly Words vs Daily Checks

GPTZero grew up around classrooms and sells a monthly allowance of words. ProofAI counts checks per day and also looks at pictures. Which one suits you depends on how you work, so this page starts from GPTZero’s own model and shows where each tool wins.

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GPTZero’s model next to ProofAI’s

Figures come from GPTZero’s and ProofAI’s public pages as of 2026-10-10. GPTZero shows different prices by country; the rupee amounts are what a visitor in India sees. “Not listed” means we found nothing on GPTZero’s own pages.

	GPTZero	ProofAI
What the quota counts	Words per month: 10,000 on Free (10,000 characters per scan), 300,000 on Premium, 500,000 on Professional	Detections per day, whatever the length of the text
Typical paid entry in India	Premium ₹599/month billed annually (₹7,188/year), or ₹1,099/month billed monthly	Starter ₹849/month or ₹8,499/year
Higher tier	Professional ₹14,388/year or ₹2,299/month	Pro ₹2,499/month; Elite ₹7,499/month
Language coverage	24 languages on a published list; Hindi is not on it	No published list yet; best on English
Plagiarism check and downloadable report	Yes, Premium and above	Neither today
LMS connection	Canvas and Google Classroom on Professional	None; an API is available
Batch upload	3 files on Free, 50 on Premium, 250 on Professional	Files up to 25 MB (PDF, DOCX, DOC, TXT); no batch upload listed
Pictures	AI image detection not listed on its pricing page	AI image detector for JPG, PNG and WebP
API entry price	From ₹4,261.69/month for 300,000 words	From ₹4,499/month
Data handling, as stated	Says it does not store or collect documents sent through its API; check its policy for the web app	Text and files not saved, but sent to AI model providers for analysis; a score record is kept in your history

Prices and limits change often. Confirm on the linked pages before you pay.

Sources: GPTZero pricing · GPTZero FAQ · GPTZero supported languages · ProofAI pricing · Liang et al. 2023, “GPT detectors are biased against non-native English writers” (arXiv)

Pick GPTZero when…

GPTZero is the stronger option in several situations, and we would rather you choose it than the wrong tool:

You check text in another language. Its list covers 24 languages. ProofAI has not published one.
You need paperwork. Plagiarism checking and downloadable reports sit in the same product from Premium upwards.
Your school runs Canvas or Google Classroom. The Professional plan connects to both.
You have one large batch. Uploading up to 250 files at once is not something ProofAI lists.
Your institution already standardised on it. Consistent results across staff beat any feature list.

Pick ProofAI when…

ProofAI makes sense if you handle pictures as well as writing, if you would rather budget in checks per day than in words per month, or if you want to try something before creating an account (ten scans a day need no login). It also suits someone who wants a cheap second opinion beside a tool they already use, which is how many reviewers use two detectors on important decisions.

A worked example: one teacher, one month

Say a teacher reads 20 essays of 1,000 words each school day, about 22 days a month. That is roughly 440,000 words. On a word quota that is more than Premium’s 300,000 and lands in Professional territory. Counted per detection it is 20 checks a day, comfortably inside Starter’s 75. The reverse holds for someone who checks three very long reports a month: a word quota barely notices them. Count your own words and your own checks before deciding.

False positives and the Stanford finding

Both tools can wrongly flag human writing. In a 2023 Stanford study, seven detectors that existed then flagged 61.3% of essays written by non-native English speakers (TOEFL essays) as AI-generated on average (Liang et al. 2023). That is older data on older detectors and says nothing about how GPTZero or ProofAI perform today, but it is the reason to treat any score as a prompt for a conversation rather than proof. We have not run GPTZero on a test set of our own, so we publish no head-to-head accuracy figure.

A one-week parallel test

Log your volume
For five days, note how many texts you check and how long they are.
Run both on the same items
Use the checker above for ProofAI and your usual GPTZero login for the other, and add two texts you know a person wrote.
Compare the highlights
Passages that both tools mark deserve a close read; passages only one marks deserve a question, not a verdict.
Choose by the numbers
Weigh your word count against detections per day, then check whether you need images, languages or LMS links.

Frequently Asked Questions

Yes, GPTZero has a free plan: 10,000 words per month and 10,000 characters per scan, per its pricing page on 2026-10-10.

Hindi is not on GPTZero’s published list of 24 languages as of 2026-10-10. ProofAI has no published list either, so neither is a documented fit for Hindi.

We found no AI image detector on GPTZero’s pricing page. ProofAI has a separate AI image detector.

GPTZero’s API starts around ₹4,261.69/month for 300,000 words; ProofAI’s starts at ₹4,499/month with domain-restricted keys. Compare against your real volume, because the units differ. See the API platform.

We have not tested GPTZero against ProofAI, and vendor figures come from different data. Run both on texts you know. Our own published numbers are on the accuracy page.

Yes. Keep your current tool for routine checks and send borderline texts to the second. Agreement between differently trained detectors counts for more than one score.