IsThisAiWritten vs GPTZero: no account, no character limit, no upload
IsThisAiWritten vs GPTZero is mostly a question of limits and privacy. IsThisAiWritten is free, needs no account, has no character limit and no monthly allowance to run out of, and the text you check never leaves your device. GPTZero takes up to 10,000 characters without an account, gives free accounts 10,000 words a month, and its FAQ says text pasted into its dashboard is stored. Which one fits depends on the text in front of you and what you plan to do with the result.
Our verdict: for long documents, private drafts or regular checks without a subscription, use IsThisAiWritten: the whole text goes in at once, every word is scanned, and nothing is uploaded or logged. GPTZero suits teachers who want Writing Replay or links into Canvas and Google Classroom, and anyone checking text in a language other than English.
IsThisAiWritten vs GPTZero, feature by feature
GPTZero details are as listed on its site at the time of writing (October 2026).
| IsThisAiWritten | GPTZero | |
|---|---|---|
| Cost | Free | Free tier; Premium $23.99 a month or $12.99 billed yearly |
| Check without an account | Any length | Up to 10,000 characters |
| Monthly allowance | Unlimited | 10,000 words free; 300,000 or 500,000 on paid plans |
| Longest single check | No limit | 50,000 characters on Premium, 150,000 on Professional |
| A 40,000-word dissertation | One pass, pasted or opened as a .docx file | Several pieces, even on Professional |
| Where your text goes | Stays in your browser, never uploaded | Dashboard inputs stored and used in aggregate |
| Report | Outcome, AI-likeness score, sentence map, style notes with one-click plainer wording | Sentence highlighting and mixed AI and human detection |
| Invisible-character cleaner | Yes | Not listed |
Where IsThisAiWritten wins
Long documents in one pass
GPTZero counts characters per scan and words per month. Without an account you can paste 10,000 characters, roughly 1,500 to 1,700 words of ordinary prose. Paid plans raise that to 50,000 or 150,000 characters. A 40,000-word dissertation runs to something like a quarter of a million characters, so even GPTZero Professional needs it in pieces. IsThisAiWritten has no word or character limit. Paste the whole document, or open a .docx file, and it is analysed in one go. Every word is scanned, never sampled, and above 30,000 words the text is shown in pages of 5,000 words with a chapter jump menu.
No account and no meter
GPTZero's free account allows 10,000 words a month, which is a handful of essays. After that you wait for next month or pay. We have no allowance to track and no login to remember. That matters most for people who check often but don't want a subscription, such as a tutor reading drafts every week.
Privacy that doesn't depend on a policy
GPTZero sets out its privacy commitments clearly: it says it is SOC 2 Type II compliant, follows FERPA and GDPR rules and deletes personal data on request. Its FAQ also says it stores what you paste into the dashboard and uses that data in aggregate to improve the service. IsThisAiWritten works differently: the detection model runs in your browser, so the text is never uploaded and there is nothing to store, share or delete. For a teacher handling students' work, that removes a data-protection question entirely.
A report that explains itself
Instead of a single score, our report gives an outcome (Human, Mixed, AI or Inconclusive) with a confidence word, an AI-likeness score ("more AI-like than X% of human writing we tested") and a sentence map showing which parts lean AI relative to the rest. Style notes point out common AI habits and offer plainer wording in one click. Writers and editors also get an invisible-character cleaner for zero-width characters and look-alike letters, and a narrative fingerprint for fiction based on the StoryScope research (Russell et al., COLM 2026). How the detector is built and tested is set out on the methodology page.
Where GPTZero is better, and when to choose it: GPTZero supports five languages to our one. Writing Replay plays back how a Google Doc was typed, pastes included, and its Chrome extension and Canvas and Google Classroom integrations make it a real classroom tool. Professional plans add batch uploads of up to 250 files, and there is an API for developers. Choose GPTZero when the text isn't in English, when you need a record of how a document was written, or when you want detection inside your school's systems.
How to use IsThisAiWritten and GPTZero together
- Paste the full text into IsThisAiWritten, however long it is.
- Read the outcome and the sentence map to find the passages that lean most AI.
- If you want a second opinion, run those passages through GPTZero, within its character limit.
- Talk to the writer before acting. A score, ours or anyone's, should never be the only evidence.
If you are a student worried about being wrongly flagged, neither tool can promise what another detector will say. Your drafts and version history are better evidence than any score, and GPTZero's Writing Replay is built around the same idea. Our guide on what to do if you're wrongly flagged covers the next steps.
Sources
- GPTZero homepage, checked October 2026
- GPTZero pricing, checked October 2026
- GPTZero FAQ, checked October 2026
- GPTZero privacy and security, checked October 2026
- Russell et al., StoryScope (COLM 2026), checked October 2026
Questions
Will IsThisAiWritten give the same result as GPTZero?
Not necessarily. The two use different models and thresholds, so they can disagree on the same text. A result from either is an estimate, never proof.
Is this AI written? Check it now.
Free, no sign-up, no word limit. The check runs in your browser, so your text never leaves your device.
Check text freeIsThisAiWritten is not affiliated with, endorsed by or sponsored by any company named on this page. Product names belong to their owners. Facts about other products come from their public pages on the date shown and may have changed since.