Scribbr AI detector
Vendor Scribbr Official site scribbr.com/ai-detector How this card is sourced
Updated · AI Detector Index editors
Scribbr's AI Detector runs unlimited free AI checks with no sign-up required, according to the Scribbr AI Detector page read 8 November 2026. Scribbr is part of QuillBot, within the Learneo family of businesses, as stated on the Scribbr about page read the same day. This card is one of twenty-two in the detector register, each built on the same fields. How this card is sourced.
What Scribbr detects
| Field | Value | Source |
|---|---|---|
| Content types detected | Text | scribbr.com/ai-detector |
| Generators covered | ChatGPT, Gemini, Copilot, GPT2, GPT3, GPT3.5, GPT4 (experimental in free tool; supported in Premium) | scribbr.com/ai-detector |
| Languages | English | scribbr.com/ai-detector |
| Free tier | Unlimited free AI checks, no sign-up required | scribbr.com/ai-detector |
| Data retention | Confidentiality guaranteed: Rest easy knowing your submissions remain private; we do not store or share your data. Submissions will never be added to our content database. | scribbr.com/ai-detector |
| Ownership | Part of QuillBot, within the broader Learneo family of businesses (founded 2012) | scribbr.com/about-us |
| Independent studies | 1 record | Studies index |
Scribbr's AI Detector checks text only. The vendor names ChatGPT, Gemini, Copilot, GPT2, GPT3 and GPT3.5 as covered generators, with GPT4 marked experimental in the free tool and supported in Premium, per the detector page read 8 November 2026. English is the only language listed on that page.
The detector page FAQ says the free tool detects GPT2, GPT3 and GPT3.5 "with average accuracy", while the body of the same page says "with high accuracy". The card carries the FAQ wording because the FAQ is the help text and the more cautious of the two statements (scribbr.com/ai-detector/, read 8 November 2026). Scribbr also says the detector "can make mistakes if the AI output was prompted to be less predictable or was edited or paraphrased after being generated".
On retention, Scribbr says: "Rest easy knowing your submissions remain private; we do not store or share your data. Submissions will never be added to our content database" (detector page, read 8 November 2026). Two related cards sit close to Scribbr in the index: QuillBot, the sister brand under Learneo, and Turnitin, the other detector aimed squarely at academic work.
Limits and plans
| Plan | Price | Limits | Checked on |
|---|---|---|---|
| Premium AI Detector with premium plagiarism check, Small document (Up to 7,499 words) | $19.95 | Premium plagiarism check plus free access to Scribbr's AI Detector and AI Proofreader; unlimited rechecks. Prices are per check, not a subscription. No standalone detector subscription. | |
| Premium AI Detector with premium plagiarism check, Regular document (7,500 - 49,999 words) | $29.95 | Same as Small document. | |
| Premium AI Detector with premium plagiarism check, Large document (50,000+ words) | $39.95 | Same as Small document. |
Free checks are unlimited and need no account, per the detector page read 8 November 2026. Paid access is sold per document through the premium plagiarism check, which includes the AI Detector and AI Proofreader with unlimited rechecks. Scribbr sells no detector-only subscription.
All three prices come from the Scribbr plagiarism checker page read 8 November 2026. They are in US dollars and charged once per check, not as a recurring plan. The free tier has no stated period: Scribbr describes it as unlimited checks rather than an allowance per day or per month.
What the vendor claims
Unfortunately, we can't guarantee 100% accuracy. Our research into the best AI detectors indicates that no tool can provide complete accuracy; the highest accuracy we found was 84% in a premium tool or 68% in the best free tool. Free detector: GPT2, GPT3, and GPT3.5 with average accuracy.
Scribbr says: "Unfortunately, we can't guarantee 100% accuracy." The same passage says Scribbr's own research into AI detectors found that no tool provides complete accuracy, with "the highest accuracy we found was 84% in a premium tool or 68%" in a free one. Scribbr also says: "Free detector: GPT2, GPT3, and GPT3.5 with average accuracy." All three statements are on the Scribbr AI Detector page (scribbr.com/ai-detector/, read 8 November 2026).
The 84% and 68% figures describe Scribbr's own comparison of detection tools, so they are a statement about the field rather than a measurement of Scribbr's detector. Scribbr adds: "Note that no AI Detector can provide complete accuracy (see our research). As language models continue to develop, detection tools will always have to race to keep up with them" (same page, read 8 November 2026).
What independent studies found
- AIDI-S-0003Walters 20232023
Scribbr: 88% of 126 documents correct, 11% incorrect, 1% uncertain; 100% correct on 42 GPT-3.5 papers, 69% on 42 GPT-4 papers; 95% of 42 human papers correct, 2% incorrect (false positive rate 2%). Tested June 25 to July 12, 2023.
Walters 2023 ran Scribbr against 126 documents between June 25 and July 12, 2023. Scribbr classified 88% correctly, 11% incorrectly and 1% uncertain; all 42 GPT-3.5 papers were caught and 69% of the 42 GPT-4 papers. On 42 human-written papers, 95% were correct and 2% were labelled AI, a 2% false positive rate (Walters 2023 PDF, read 8 November 2026).
The 2% rests on a base of 42 human papers tested in mid-2023 against models Scribbr has since moved past. A flag from Scribbr today is a reason to look closer, not a finding on its own.
Where Scribbr appears in the index
Rankings
- AIDI-R-01AI detectors ranked by independent testing Two records added in the fifth wave on 9 November 2026, Pegoraro 2023 and Fleckenstein 2024, changed nine counts and none: Pegoraro 2023 tested ZeroGPT, GPTZero, Copyleaks, Originality.ai, Writer, Content at Scale (BrandWell), DetectGPT, the GPT-2 Output Detector and GLTR, lifting GPTZero to 12, the GPT-2 Output Detector to 10, Copyleaks to 7 and Originality.ai and ZeroGPT to 6; Fleckenstein 2024 tested 289 teachers and no software, so it counts for no card ([Fleckenstein 2024 record](/studies/fleckenstein-2024-teachers/)). Illuminarty, one of four cards added in the same wave, joined with its one image record from Ha and Passananti 2024, so 18 of 72 cards now qualify.
- AIDI-R-02AI detector false positive rates, ranked
- AIDI-R-04AI detectors ranked by languages supported
- AIDI-R-06AI detectors ranked by stated data retention
- AIDI-R-17AI detectors ranked by the generator models the vendor names
Fits these use cases, questions and comparisons
- AIDI-U-04AI detectors for job applications and recruiters
- AIDI-U-08AI detectors for researchers checking their own manuscripts
- AIDI-U-10AI detectors for grant and proposal reviewers
- AIDI-C-07ZeroGPT vs Scribbr vs QuillBot: three free AI detectors on the same 14 fields
- AIDI-C-10Scribbr vs Turnitin AI detection: the 14 fields and the study results side by side
- AIDI-C-11Scribbr vs QuillBot AI detector: two Learneo brands on the same 14 fields
Scribbr appears in three rankings. AI detectors ranked by independent testing lists one study for Scribbr, Walters 2023. AI detector false positive rates carries the 2% figure from Walters 2023 on 42 human papers. AI detectors by languages supported places Scribbr at one language, English, per the detector page read 8 November 2026.
Among the audience views, Scribbr sits on AI detectors for job applications, because the detector is free and text only. Since 9 November 2026 Scribbr also ranks first in stated data retention on its "we do not store or share your data" line, and the Learneo line on its about page anchors the ownership map beside QuillBot. The full detector hub lists all twenty-two cards side by side with the same fields.
Two comparisons added 9 November 2026 read this card beside other tools on Walters 2023, its one record: Scribbr vs Turnitin and ZeroGPT vs Scribbr vs QuillBot.
Questions about Scribbr AI detector
Is Scribbr's AI Detector free?
Yes. Scribbr says free AI checks are unlimited and need no sign-up, per the detector page read 8 November 2026. Paid access to the Premium AI Detector comes bundled with a plagiarism check priced per document at $19.95, $29.95 or $39.95 USD by length, per the Scribbr plagiarism checker page read the same day.
What false positive rate did Scribbr show in independent testing?
Two percent. In Walters 2023, Scribbr labelled 2% of 42 human-written first-year composition papers as AI, while 95% were classed correctly. The test ran June 25 to July 12, 2023, so the result describes the detector as it stood then, on GPT-3.5 and GPT-4 era text.
Does Scribbr's AI Detector support languages other than English?
No. English is the only language on the Scribbr detector page read 8 November 2026, which is why Scribbr ranks at one language on the languages ranking. Other cards in the index list between four and thirty languages, so a non-English document needs a different card.
Does Scribbr sell a detector-only subscription?
No. Scribbr sells the Premium AI Detector only as part of a per-check plagiarism bundle at $19.95, $29.95 or $39.95 USD, with no subscription, per the plagiarism checker page read 8 November 2026. Free checks remain unlimited, and the free tool marks GPT4 detection as experimental.
Sources and revisions
Sources
- scribbr.com/ai-detectorRead 8 November 2026
- scribbr.com/about-usRead 8 November 2026
- scribbr.com/plagiarism-checkerRead 8 November 2026
- degruyterbrill.com/document/doi/10.1515/o...Read 8 November 2026
). Illuminarty, one of four cards added in the same wave, joined with its one image record from Ha and Passananti 2024, so 18 of 72 cards now qualify.: register plate](/img/independently-tested-480.webp)
