Do free AI detectors keep my text?

Some do. Copyleaks uses scans for training unless you opt out, QuillBot trains on inputs by default, and Originality.ai says text in its free checker may be used for training. Pangram and ZeroGPT say they don't train on your text. Check the privacy policy before pasting anything confidential.

Best Free AI Detectors in 2026: What You Actually Get Free

The best free AI detectors in 2026 are IsThisAiWritten for unlimited, private checks with no sign-up, Pangram's free plan for the strongest independent test record, and GPTZero for a quick check without an account. "Free" means very different things from one tool to the next, though: a few hundred words a day, a daily scan count, a feature locked behind a paywall, or your text used for training. This guide ranks the free tiers on what they actually give you.

Quick picks. No caps of any kind, and nothing uploaded: IsThisAiWritten. Strongest independent test results on a free plan: Pangram, if you don't mind signing up. One quick scan with no account: GPTZero. For schools: Copyleaks, with a generous free scan and paid plans that connect to most LMS platforms.

The best free AI detectors compared

What each free tier included at the time of writing (October 2026).

Tool	Free allowance	Account	Locked behind payment	Your text
IsThisAiWritten	No limit	None	Nothing	Never uploaded
Pangram	20 credits a day, about 2,000 words	Required	Plagiarism check, some extension features	Saved to history; never used for training
GPTZero	10,000 characters per scan; 10,000 words a month with an account	Not needed for one scan	Sentence highlights, larger scans	Dashboard text stored
Copyleaks	25,000 characters per scan	Not needed	Sentence-level detail needs a free account	Used for training unless you opt out
Originality.ai	2,000 words, 3 scans a day	Not needed	Plagiarism and fact checks	May be used for training
Scribbr	1,200 words, unlimited checks	Not needed	25,000-word premium check	Page says not stored; policy allows training
QuillBot	1,200 words, 6 scans a day	Not stated	Unlimited length, reports	Used for training by default
ZeroGPT	15,000 characters per check	Not stated	Longer checks, batch files	Says not saved or trained on

1. IsThisAiWritten

Best for: unlimited, private checks of anything from a paragraph to a novel.

This is our own tool, so here is the plain version. It is completely free: no account, no word or character limit, no daily cap and no paid tier holding features back. A 208,000-word novel goes through in one go, every word is scanned rather than sampled, and .txt or .docx files are read on your device. The detector downloads once and runs in your browser, so your text never reaches a server. You get an outcome (Human, Mixed, AI or Inconclusive), an AI-likeness figure, a sentence map, style explanations with a plainer wording one click away, and an invisible-character cleaner.

Like any detector, it can be wrong in both directions, so treat a result as a reason to look closer, not as proof. Our methodology explains how it is tested.

Pro: no limits, no sign-up and nothing uploaded.
Pro: every feature is free, and the methodology is public.
Con: English only.
Con: 50-word minimum, so very short snippets can't be checked.

The catch: the first check downloads a 131 MB model, which is slow on a weak connection. After that, the model is cached.

2. Pangram (free plan)

Best for: free checks from the detector with the strongest independent record.

Pangram's free plan gives you 20 credits a day, which Pangram puts at about 2,000 words, plus file uploads and three AI image scans a day. That is small. The reason to put up with it is the detector itself, which has done best in every independent study we found (see how accurate is Pangram).

Pro: the strongest record in independent studies, free or paid.
Pro: Pangram says it never trains on your data.
Con: you must create an account before the first scan.
Con: about 2,000 words a day, so a single long essay can use the whole day's allowance.

The catch: scans are kept in your history until you delete them.

3. GPTZero (free)

Best for: one free scan, without signing up, from a widely tested detector.

Paste up to 10,000 characters on GPTZero's homepage and you get a result without signing up. A free account raises that to 10,000 words a month and adds one "advanced" scan. GPTZero has been through more independent tests than most free tools, and they found it rarely flags human writing but misses much text that has been through a humanizer; see how accurate is GPTZero.

Pro: no account needed for a single scan.
Pro: a free account adds a monthly allowance, useful for regular checks.
Con: sentence-level highlighting is listed with the paid plans.
Con: weaker on text that was rewritten by a humanizer tool.

The catch: GPTZero says it stores text submitted through its dashboard and uses it in aggregate to improve the service.

4. Copyleaks (free)

Best for: long free checks without logging in, and AI detection in many languages.

Copyleaks scans up to 25,000 characters without an account, in more than 30 languages. Sign up for a free account and you also get sentence-by-sentence insights and a limited number of credits.

Pro: a bigger no-login scan than GPTZero or ZeroGPT.
Pro: AI detection in over 30 languages.
Con: the most useful detail needs an account.
Con: missed much of the AI content in the 2026 academic study.

The catch: Copyleaks' privacy policy says scans are used to train its models; you can opt out by contacting support.

5. Originality.ai (free)

Best for: writers and site owners checking a few articles a day.

Three free AI scans a day, up to 2,000 words each, no account needed. That suits someone checking a handful of blog posts rather than a stack of essays. The detector behind the free box has a good independent record, which our accuracy ranking covers.

Pro: generous per-scan size for articles.
Pro: file uploads (.docx, .pdf, .doc) on the free tier.
Con: three scans a day and a 100-word minimum.
Con: plagiarism and fact checks are paid.

The catch: Originality.ai says text entered in its free detector may be used for training; account holders can opt out.

6. Scribbr (free)

Best for: students checking essay-length text again and again.

Scribbr has no daily cap: unlimited checks of up to 1,200 words, with no account. Results are sorted into four categories, including "human-written and AI-refined", with feedback by paragraph. Scribbr's page quotes its own research, which found the best free tool it tested reached 68% accuracy and the best premium tool 84%.

Pro: unlimited checks, no sign-up.
Pro: distinguishes AI-refined text from fully AI-written text.
Con: 1,200 words per check.
Con: the longer premium check is sold per document with a plagiarism scan.

The catch: the detector page says submissions are not stored, but Scribbr's privacy policy says collected data may be used to train its models.

7. QuillBot (free)

Best for: checking text written in languages other than English.

QuillBot's free detector takes up to 1,200 words per scan, six scans a day, and supports more than 20 languages. It labels text as AI-written, human-written, or human-written with some AI refinement. QuillBot cites a 99% detection rate from its RAID leaderboard entry, which it submitted in January 2025.

Pro: many languages and a clear "AI-refined" label.
Pro: free users get one explainer card on top of the score.
Con: six scans a day; 80-word minimum.
Con: reports and unlimited length are Premium features.

The catch: QuillBot uses inputs for training by default. The opt-out is in its browser extension.

8. ZeroGPT (free)

Best for: quick checks where privacy matters and a rough signal is enough.

ZeroGPT's free box takes 15,000 characters. Its FAQ makes one of the strongest privacy statements of any free tool here: checked text is "not saved, shared, published online, or used to train" its model. It claims 98.4% accuracy, but in the most detailed independent test we found, the 2024 RAID paper, the authors could not set ZeroGPT to a 5% false positive rate in many text domains.

Pro: large free check and a strong privacy promise.
Pro: sentence highlighting on the free tool.
Con: little recent independent evidence on accuracy.
Con: batch uploads and longer checks need a paid plan.

The catch: its privacy policy is worded more cautiously than its FAQ.

Other free checkers we looked at

Grammarly has a free AI detector page and a free Authorship feature that records how a document was written. Highlighted AI detection inside the editor needs Pro.
Decopy takes up to 200,000 characters with no sign-up, but limits visitors to five uses (ten with an account). It publishes no accuracy figures.
Quetext checks up to 1,000 words free with no sign-up. Its FAQ says scans are not stored or used for training, while its privacy policy, updated in October 2026, says user content may be used for AI training.
Sapling checks only the first 2,000 characters for free, but its paid API is among the cheapest.

How we compared

IsThisAiWritten is listed first because it is our own tool and the free, private option with no limits. We ranked the other free tiers on three things: how good the underlying detector is according to independent research, how much you can check without paying, and what you give up in return (an account, daily caps, or use of your text). Between 16 and 18 October 2026 we opened each tool's own product, pricing and privacy pages. Where a product page and a privacy policy disagree, we report both. We did not run our own accuracy tests of these tools; accuracy notes come from published studies or are labelled as the vendor's claim.

Sources

Pangram, What do I get with a free account?, checked October 2026
Pangram, Does Pangram train on my data?, checked October 2026
Pangram, How to view your past scans, checked October 2026
GPTZero homepage, checked October 2026
GPTZero pricing, checked October 2026
GPTZero, Are you storing data from API calls?, checked October 2026
Copyleaks AI Detector, checked October 2026
Copyleaks privacy policy, checked October 2026
Originality.ai homepage and FAQ, checked October 2026
Originality.ai pricing, checked October 2026
Scribbr AI Detector, checked October 2026
Scribbr privacy policy, checked October 2026
QuillBot AI Detector, checked October 2026
QuillBot, How does QuillBot use my data?, checked October 2026
ZeroGPT FAQ, checked October 2026
ZeroGPT pricing, checked October 2026
Grammarly AI Detector, checked October 2026
Grammarly Authorship, checked October 2026
Decopy pricing, checked October 2026
Quetext AI Detector, checked October 2026
Quetext privacy policy, checked October 2026
Sapling AI Content Detector, checked October 2026
Jabarian and Imas, Artificial Writing and Automated Detection, checked October 2026
Van Vlasselaer, Van Droogenbroeck and Spruyt (2026), checked October 2026
Dugan et al., RAID benchmark paper, checked October 2026

The best free AI detectors in 2026, and what each free tier really includes