Best Free AI Content Detectors 2026: 6 Options Compared

No AI detector can tell you for certain that a person wrote a text, and every vendor in this list says so in its own fine print. What they give you is a probability score, which is useful as one input and unreliable as proof. That is the first thing to know before choosing a free tool: use it to check your own drafts or to flag text for a closer human read, not to accuse a student or a freelancer. The free tools differ mostly in how much text you can paste at once. ZeroGPT shows a 15,000-character counter on its free text box, Sapling checks up to 2,000 characters per run, and Quetext gives you 1,000 words across its checker. Copyleaks and GPTZero also offer free tiers, so check their pages for current limits before you plan around a number. If you need to scan a long essay, ZeroGPT has the roomiest free box; for short snippets in a browser extension, Sapling is quicker. The trade-off is consistency: run the same paragraph through two detectors and the scores can disagree widely, so treat a single high score as a prompt to read the text, not a verdict.

ZeroGPT

The roomiest free box here: the text detector shows a 15,000-character counter, highlights sentences and needs no card. Check which features are free and which are paid before relying on it.

Price: Free (Free plan at $0 with no card; the free text detector shows a 15,000-character counter) (ZeroGPT pricing, checked 2026-10-23).

Platforms and license: Web. Proprietary SaaS.

Best for: Checking a long draft in one paste.

Sapling

Free AI detector checks up to 2,000 characters per run, alongside basic writing help and a browser extension. Short limit, so long essays need several pastes; Pro is $12 a month billed annually.

Price: Free (basic writing assistance and AI detector checks up to 2,000 characters per check); paid from $12 per month, billed annually ($25 billed monthly, Pro) (Sapling pricing, checked 2026-10-22).

Platforms and license: Web, Browser extension. Proprietary.

Best for: Quick checks on emails and short passages.

Quetext

Free plan allows 1,000 words in the plagiarism checker and AI detector together, with a summarizer and humanizer on the same login. Useful when you want plagiarism and AI checks in one place; paid from $14.99 a month.

Price: Free (Free plan at $0 per month: 1,000 words for the plagiarism checker and AI detector, 2,000 for the AI summarizer, 500 for the AI humanizer); paid from $14.99 per month (Essential, 100,000 words a month; monthly and yearly options shown, no annual price listed) (Quetext pricing, checked 2026-10-22).

Platforms and license: Web. Proprietary.

Best for: Writers who also need a plagiarism check.

Copyleaks

A well-known detector with a free trial plan reported at about 10 pages a month. The vendor pricing page returned an error to our fetch, so that figure comes from a search listing; verify before relying on it.

Price: Free (Free trial plan of about 10 pages (roughly 2,500 words) a month) (Copyleaks pricing, checked 2026-10-22).

Platforms and license: Web. Proprietary.

Best for: Educators who want a second opinion.

GPTZero

Built for education use, with a free plan that third-party trackers put at a monthly word allowance. Check the vendor pricing page for the current free limits.

Price: Free (GPTZero pricing, checked 2026-10-23).

Platforms and license: Web. Proprietary SaaS.

Best for: Teachers and students checking essays.

QuillBot

Sits beside QuillBot's paraphraser and summarizer, so one account covers several writing checks. Check its pricing page for current free limits and the Premium price.

Price: Free (QuillBot pricing, checked 2026-10-23).

Platforms and license: Web, Browser extension. Proprietary.

Best for: People already using QuillBot for editing.

Compare: QuillBot alternatives

Which one to pick

• You need to check a long essay in one go: ZeroGPT
• You only check short emails or snippets: Sapling
• You also need a plagiarism scan: Quetext
• You are a teacher wanting a second opinion: GPTZero