Scribbr AI Detector: Review & Free Check
Paste any text below for a free AI score, no account needed. This is Humanit's checker, not Scribbr's. Under it: what Scribbr's free detector gives you, what its AI-refined label means, and how much to trust it.
Scribbr's AI detector is a free, student-focused checker: unlimited checks with no account, up to 1,200 words per submission. It sorts writing into human-written, AI-generated and AI-refined, gives paragraph-level feedback, and Scribbr itself says no AI detector can provide complete accuracy.
Works with every major AI model
How it works
- 1Paste your text. Drop in the writing you want to check against Scribbr-style detection.
- 2Run the free detector. Humanit returns a 0–100 AI-likelihood score, a verdict, and the signals behind it.
- 3See what reads as AI. The subscores show which patterns — predictable phrasing, uniform rhythm, stock vocabulary — are pulling the score up.
- 4Fix it if needed. If it reads as AI, send it to the humanizer to rewrite those signals, then re-check.
What Scribbr's free detector gives you
Scribbr built its detector for students checking their own essays, and the free version is generous: unlimited checks, no account, up to 1,200 words per submission. It flags the specific areas it reads as AI-generated or AI-refined and gives paragraph-level feedback rather than one bare number. It also supports several languages beyond English, including German, French and Spanish.
Human-written, AI-generated, or AI-refined
The most useful thing about Scribbr's output is the middle category. Scribbr says its detector distinguishes fully AI-generated writing from AI-refined writing — human text that has been polished with AI tools — and completely human writing. That matters because most real student writing now sits in the middle: a draft you wrote yourself and then ran through a grammar tool or a paraphraser. If Scribbr marks a passage AI-refined, it is telling you the phrasing has been smoothed in a way detectors associate with AI editing, not that a chatbot wrote your essay. Grammarly-style editing is a common cause; the Grammarly AI detector page explains why.
Scribbr sends you to QuillBot
One detail most reviews miss: Scribbr's own detector page suggests that if you want a more advanced and reliable check, you can also try QuillBot's AI detector. It is an unusually candid pointer, and worth taking seriously — the QuillBot AI detector page covers what that tool's free tier gives you. Scribbr also sells an AI humanizer and paragraph and sentence rewriters alongside the detector, so it plays on both sides of the detection question, as most writing companies now do.
How accurate is Scribbr's AI detector?
Scribbr says its checker detects the latest models, like GPT-4, with high accuracy — and, to its credit, states on the same page that no AI detector can provide complete accuracy, because detection tools are in a constant race with new models and humanizers. That is the honest framing. Independent research on detectors as a class backs it up: a 2023 peer-reviewed study in Patterns found more than 61% of genuine TOEFL essays by non-native English speakers misclassified as AI, and every detector struggles more with edited AI text than with raw output. Use Scribbr's result to find passages worth a closer look, not as a verdict.
What to do if Scribbr flags your writing
If the writing is yours, look at what the flagged paragraphs have in common. Detectors react to even sentence rhythm, stock transitions such as "moreover" and "in conclusion", and generic claims without specifics — so vary sentence length, cut filler transitions and add the concrete detail only you would know. Keep your drafts and version history; they are stronger evidence of authorship than any detector score. If the text is AI-assisted and that is allowed for your task, rewrite it properly and re-check. And remember that your school may run a different tool entirely — often Turnitin — so a clean Scribbr score is not a promise about anyone else's.
A second check, with the reasoning shown
Humanit's detector above is free with no account for up to 300 words per check — a smaller free limit than Scribbr's, to be straight about it. What it adds is the breakdown: a 0–100 score split into sub-signals like perplexity, burstiness, AI vocabulary and structure, with the exact phrases pulling the score up, and a humanizer on the same page if something needs rewriting. Two detectors disagreeing on the same text is normal and tells you the passage sits in a grey zone.
Who it's for
| Feature | Scribbr AI detector | Humanit detector |
|---|---|---|
| Free check without an account | Yes, unlimited, up to 1,200 words each | Yes, up to 300 words per check |
| Result categories | Human-written, AI-generated, AI-refined | 0–100 score with a verdict |
| Explains why | Paragraph-level feedback | Sub-signals plus the exact phrases that read as AI |
| Languages | Several, including German, French, Spanish | English-tuned |
| Rewrite flagged text in place | Separate AI humanizer product | Yes, humanizer on the same page |
Frequently asked questions
Is this the official Scribbr AI detector?
No. This is Humanit's free detector for the same job, so you can get a second opinion on a draft. Scribbr's own detector is on scribbr.com.
Is Scribbr's AI detector free?
Yes. Scribbr offers unlimited free checks with no account, up to 1,200 words per submission.
Is Scribbr's AI detector accurate?
Scribbr says it detects the latest models with high accuracy and also states that no AI detector can provide complete accuracy. Independent research finds real false positives across detectors, especially for non-native English writers, so treat a Scribbr score as a signal, not proof.
What does AI-refined mean on Scribbr?
It means the detector thinks human writing has been polished with AI tools, such as an AI grammar checker or paraphraser, rather than generated from scratch. It is an estimate about the style of the text, not a record of how it was written.
Is Scribbr the same as QuillBot?
They are separate products, but Scribbr's detector page itself suggests trying QuillBot's AI detector if you want a more advanced check.
Can Scribbr detect ChatGPT?
Scribbr says it detects text from ChatGPT, Copilot, Gemini and other popular tools. Like every detector it is most reliable on long, unedited AI output and least reliable on edited or mixed writing.
Will my text be used to train AI?
No. Your text is sent to the model only to produce your result and is never used to train any AI. No content is stored beyond the request.
Does it keep my original meaning?
Yes. Humanit preserves your facts, numbers, names, and citations while changing the phrasing and structure. It never invents new claims.