Does Scribbr detect AI?
Yes, Scribbr has an AI detector. The free version checks up to 1,200 words at a time with no sign-up, in English, Spanish, German and French, and labels parts of your text as AI-generated, AI-refined or human-written. Schools don't grade with it, so its score can't tell you what Turnitin or your school's own checker will say.UpdatedWhat Scribbr's AI detector checks
Paste a text into Scribbr's AI detector and it returns a percentage from 0% to 100%: how much of the text it thinks was written or refined with AI. It also gives feedback paragraph by paragraph, sorting each part into one of four groups: AI-generated, AI-generated and AI-refined, human-written and AI-refined, or human-written. The AI-refined labels are meant for text that a paraphraser or similar tool reworked.The free version allows unlimited checks of up to 1,200 words each, with no account. A premium AI check comes free with Scribbr's paid plagiarism check and has no word limit; Scribbr says the premium version is the more accurate one. The AI detector doesn't check for plagiarism, and Scribbr says it doesn't store or share the text you submit.How accurate is Scribbr's AI detector?
Scribbr says no detector, its own included, is 100% accurate. Its main evidence is its own test of 12 detectors, last revised in July 2026, on 30 short texts: human writing, ChatGPT output, a mix of the two, and texts run through QuillBot's paraphraser. Scribbr's premium detector came first at 84%, and its free detector tied with QuillBot's for second at 78%. Copyleaks scored 66% and GPTZero 52%. Turnitin wasn't in the test.Read those numbers with two caveats. Scribbr ran the test and ranked its own product first, and QuillBot, which tied for second, is its sister company: Scribbr is part of QuillBot, within the Learneo group. The AI texts also came from GPT-3.5 and GPT-4, which are older than the models most students use now. Its results on harder texts matter more: even the premium detector caught only 60% of AI text that was mixed with human writing or paraphrased, and most detectors answered close to 0% or 100% even when a text was about half and half.Scribbr vs Turnitin
They answer the same question with different models. Turnitin is licensed by schools, its AI score goes to the instructor, and scores under 20% show only as an asterisk. Scribbr is open to anyone, shows you every percentage, and uses its own labels. Scribbr doesn't say its AI detector uses Turnitin's model, and different models can give the same text very different scores.So a low Scribbr score doesn't promise a low Turnitin score, and a high one doesn't mean Turnitin will flag you. For how Turnitin reads a paper, see does Turnitin detect AI?Get a second read on your draft
Two detectors that flag the same sentences tell you more than one score. The detector below runs in your browser with no sign-up and no word limit, and scores every sentence on five writing signals: even rhythm, stock phrases, hedging and transitions, em dashes and repeated words. It isn't Scribbr or Turnitin and can't predict their scores. Use it to find the sentences worth rereading, then revise them in your own words.0 words
Is Scribbr itself AI?
Scribbr started in 2012 as a human proofreading and editing company, and it still sells human editing. It also offers AI tools: an AI proofreader, a grammar checker, a paraphrasing tool, a summarizer, an AI humanizer and the AI detector.Using this responsibly
A detector score is a signal, not proof, whichever tool gives it. Checking your own draft doesn't change your school's rules: if AI help is banned on an assignment, getting past a detector is still a breach. Where AI help is allowed, say how you used it if your course asks you to.If AI help was allowed and your final text reads stiff, Leap's humanizer swaps stock AI phrases, removes em dashes and invisible characters, adds contractions and marks sentences of the same length so you can vary them. It promises no detector result.Frequently asked questions
Yes. The free version allows unlimited checks of up to 1,200 words each, with no sign-up. A premium AI check with no word limit comes with Scribbr's paid plagiarism check; see Scribbr's site for current prices.
In Scribbr's own test of 12 detectors, its premium detector scored 84% and its free one 78%. That is the vendor testing its own tool on 30 short GPT-3.5 and GPT-4 texts, and Scribbr says no detector is 100% accurate. Mixed and paraphrased text was the hardest to catch.
There's no fair comparison: Scribbr's own test left Turnitin out, and students can't run Turnitin to compare. The scores also work differently, since Turnitin hides scores under 20% and reports only to instructors, while Scribbr shows any percentage. Treat a Scribbr score as a rough read, not a preview of Turnitin.
Scribbr doesn't say its AI detector uses Turnitin's model. Its plagiarism checker is a separate product that Scribbr says uses similar software to universities. Either way, a Scribbr score isn't the score your school's Turnitin will give.
Scribbr separates text an AI wrote from text that an AI tool, such as a paraphraser, reworked. Its four labels are AI-generated, AI-generated and AI-refined, human-written and AI-refined, and human-written.
Scribbr is a company, not a chatbot. It began with human proofreading and now also offers AI tools, including an AI proofreader, paraphraser, summarizer, humanizer and the AI detector. It is part of QuillBot, within the Learneo group.
Scribbr says it doesn't store or share text submitted to its AI detector. Leap's detector runs in your browser, and your text leaves the page only if you choose the paid Rewrite step under the result.