Scribbr vs QuillBot AI detector: two Learneo brands on the same 14 fields
Scribbr and QuillBot are two brands of one group: Scribbr's about page, read 8 November 2026, says "Scribbr is proud to be a part of QuillBot, within the broader Learneo family of businesses" (scribbr.com/about-us), and the index records both detectors under Learneo on that sentence, because QuillBot's own about page did not load on 8 or 9 November 2026. Shared ownership has not produced shared evidence: Scribbr carries 1 study record (Walters 2023, 88% of 126 documents correct, 2% of 42 human papers flagged) and QuillBot 2 (Kar 2024 and Alshammari and Rao 2025, both printing displayed scores rather than rates), and no indexed study has run both detectors on the same text (De Gruyter 10.1515/opis-2022-0158, Table 4; DOI 10.1177/02537176241247934, Table 1; arXiv 2507.17944, Table III; read 8 and 9 November 2026). The two cards are read side by side below on the same 14 fields, with the vendor's wording and the page it came from.
Updated Fields checked 8 November 2026
Short answer
Scribbr's detector is free and unlimited with no account, states English only, no input limit, no API and no integrations, and says submissions are not stored; QuillBot's detector is free for 6 scans a day of up to 1,200 words, with an 80-word minimum, 6 languages, six browser and app surfaces and a Premium plan at $8.33 a month billed annually that removes the word limit (scribbr.com/ai-detector, quillbot.com/ai-content-detector, quillbot.com/premium, read 8 November 2026). Scribbr has the only measured false positive rate of the two, 2% of 42 human papers in Walters 2023; QuillBot has two records, neither of which prints a rate on human text, and a vendor-submitted RAID leaderboard entry of 30 January 2025 at 99.62% (Walters 2023; Kar 2024; Alshammari and Rao 2025; github.com/liamdugan/raid, read 9 November 2026). The same group sells both, and neither page says whether the two detectors share a model. No detector score should be the only evidence in a misconduct, hiring or publishing decision.
How do Scribbr and QuillBot compare on the 14 fields?
| Field | Scribbr | QuillBot |
|---|---|---|
| 1. Name, vendor, official domain | Scribbr's AI Detector, Scribbr, scribbr.com | AI Detector by QuillBot, QuillBot, quillbot.com |
| 2. Modalities detected | text | text, image |
| 3. Generators covered | ChatGPT, Gemini, Copilot, GPT2, GPT3, GPT3.5, GPT4 (experimental in the free tool, supported in Premium) | GPT-6, GPT-5, ChatGPT, Gemini, Claude, Llama and "other LLMs" |
| 4. Languages supported | 1: English | 6: English, French, Spanish, German, Dutch, Portuguese |
| 5. Input limits | Minimum 80 words per scan; Free up to 1,200 words per scan; Premium no word limit; paste or upload a document (file types and size not published); Premium bulk upload | |
| 6. Free tier | Unlimited free AI checks, no sign-up required | Up to 1,200 words per scan, up to 6 scans per day, 1 free explainer card; no sign-up for scans under 1,200 words |
| 7. Paid plans | No detector subscription: premium plagiarism check with the premium AI Detector at $19.95 (up to 7,499 words), $29.95 (7,500 to 49,999 words) or $39.95 (50,000+ words) per check | Premium $8.33 a month billed annually, bundled with the writing suite: no word limit, unlimited scans, unlimited explainer cards; Team Plan, price not shown |
| 8. API | ||
| 9. Integrations | Google Chrome extension, Microsoft Edge extension, macOS app, Word add-in, Android keyboard and app, iOS keyboard and app | |
| 10. Vendor accuracy and false positive claims | "Unfortunately, we can't guarantee 100% accuracy"; the vendor's own research found "the highest accuracy we found was 84% in a premium tool or 68% in the best free tool"; free detector covers GPT2, GPT3 and GPT3.5 "with average accuracy" | "Detect AI text reliably with a 99% detection rate, according to independent evaluations from RAID"; "When the result is unclear, our model tends to classify texts as human written, which reduces false positives", no numeric rate |
| 11. Independent studies | 1 record: Walters 2023 | 2 records: Kar 2024, Alshammari and Rao 2025 |
| 12. Data retention and privacy statement | "we do not store or share your data. Submissions will never be added to our content database" | No retention statement on the detector page or in the pages read |
| 13. Launch year and ownership | Not stated; part of QuillBot, within the Learneo family of businesses | Not stated; part of the Learneo family of businesses, stated on scribbr.com, a sister Learneo brand |
| 14. Rankings the card appears in | Independently tested, false positive rate, languages, data retention, generators covered | Independently tested, languages, studies by content type, platform integrations, minimum input, free checks per day, generators covered; unlimited table of input limits |
Which studies tested Scribbr or QuillBot?
None tested both. Walters 2023 submitted 126 documents, 42 human-written first-year composition papers and 42 papers each from GPT-3.5 and GPT-4, to 16 detectors between 25 June and 12 July 2023, Scribbr among them and QuillBot not, and printed the share correct, incorrect and uncertain per tool and per set (De Gruyter 10.1515/opis-2022-0158, Table 4, read 8 November 2026). Kar 2024 ran one ChatGPT 3.5 article of under 500 words and three paraphrases of it through ten free detectors, QuillBot among them and Scribbr not, with no human text (DOI 10.1177/02537176241247934, Table 1, read 9 November 2026). Alshammari and Rao 2025 ran six detectors, QuillBot among them, on 49 DeepSeek-V3 answers, 49 human answers and paraphrased sets, and printed mean displayed scores (arXiv 2507.17944, Tables III to V, read 9 November 2026). QuillBot's vendor-submitted entry on the RAID leaderboard, dated 30 January 2025, is the figure its "99% detection rate" sentence points to; the index records it as a leaderboard entry read from the submissions repository, not as a study record (RAID 2024; leaderboard question).
| Source | Scribbr | QuillBot |
|---|---|---|
| Walters 2023, share of 126 documents correct (Table 4) | 88% correct, 11% incorrect, 1% uncertain | Not tested |
| Walters 2023, 42 GPT-3.5 papers | 100% correct | Not tested |
| Walters 2023, 42 GPT-4 papers | 69% correct | Not tested |
| Walters 2023, 42 human-written papers | 95% correct, 2% incorrect (false positive rate 2%) | Not tested |
| Kar 2024, one ChatGPT 3.5 article and three paraphrases (Table 1) | Not tested | 100% AI on the original; 90 AI after QuillBot's own paraphrase; 100 after Grammarly and ChatGPT paraphrases |
| Alshammari and Rao 2025, 49 answers per set (Tables III and V) | Not tested | Mean AI score 98.4% on DeepSeek-V3 answers; mean human score 100% on 49 human answers; 95.4% on DeepThink text, 58% after a humanized paraphrase |
| RAID leaderboard entry, vendor-submitted 30 January 2025 (read 9 November 2026) | No entry | 99.62% at a 5% false positive rate across the RAID generations, 2,497 missed, AUROC 0.9962 |
| Vendor statement, scribbr.com (read 8 November 2026) | "we can't guarantee 100% accuracy"; no tool in the vendor's research exceeded 84% (premium) or 68% (free) | |
| Vendor statement, quillbot.com (read 8 November 2026) | "99% detection rate, according to independent evaluations from RAID"; no false positive rate |
Results as each study reports them: De Gruyter 10.1515/opis-2022-0158, DOI 10.1177/02537176241247934, arXiv 2507.17944, github.com/liamdugan/raid, read 8 and 9 November 2026. "Not tested" means the paper did not run that tool. Kar 2024 and Alshammari and Rao 2025 print scores on single texts or means of displayed percentages, so neither enters the false positive rate ranking or the false negative rate ranking; Scribbr's 2% of 42 does.
What do the two cost over 12 months?
| Plan | Monthly as stated | Annual as stated | Inclusions as stated | Checked on |
|---|---|---|---|---|
| Scribbr free detector | $0 | Unlimited free AI checks, no sign-up; GPT2, GPT3 and GPT3.5 coverage, GPT4 experimental | 8 November 2026 | |
| Scribbr premium check, small document | $19.95 per check | Up to 7,499 words; premium plagiarism check with the premium AI Detector and AI Proofreader; unlimited rechecks; no subscription | 8 November 2026 | |
| Scribbr premium check, regular document | $29.95 per check | 7,500 to 49,999 words; same inclusions | 8 November 2026 | |
| Scribbr premium check, large document | $39.95 per check | 50,000+ words; same inclusions | 8 November 2026 | |
| QuillBot free detector | $0 | Up to 1,200 words per scan, 6 scans a day, 1 free explainer card; no sign-up under 1,200 words | 8 November 2026 | |
| QuillBot Premium | $8.33 per month, billed annually (monthly price not shown with the annual toggle on) | $99.96 at the stated monthly rate times twelve | Full access to the AI Detector with no word limit, unlimited scans and explainer cards, bundled with the paraphraser, grammar checker and the rest of the suite; no detector-only plan | 8 November 2026 |
| QuillBot Team Plan | Price not shown | Price not shown | "Explore Team Plan" on the premium page | 8 November 2026 |
Prices in USD as shown on scribbr.com/plagiarism-checker and quillbot.com/premium, checked 8 November 2026. Scribbr sells per check, so a 12-month figure depends on how many documents are checked; a student who checks four documents of under 7,500 words in a year pays $79.80 with Scribbr's premium bundle against $99.96 for QuillBot Premium at the stated annual rate, and nothing with either free tool. QuillBot's $99.96 is the index's multiplication of the stated $8.33 by twelve; the page shows the monthly figure under an annual toggle and does not print the yearly total.
One of the comparisons in the compare hub. The cards are Scribbr and QuillBot, and the home board answers which AI detectors exist and who has tested them? A student who already uses one Learneo tool and wonders whether the sister brand's detector will read a draft differently is the reader this pair is written for; the shared-owner question records the ownership line and the two other groups in the index with more than one card.
Which card fits which reader?
- Choose Scribbr ifyou want unlimited free checks of any length with no account and a written no-storage line (scribbr.com/ai-detector, read 8 November 2026). QuillBot's free tier stops at 1,200 words and 6 scans a day.
- Choose Scribbr ifa measured false positive rate matters more than a vendor figure: 2% of 42 human papers in Walters 2023 is the only rate on human text either card carries (De Gruyter, Table 4).
- Choose QuillBot ifyour text is in French, Spanish, German, Dutch or Portuguese: Scribbr states English only (quillbot.com/blog, scribbr.com/ai-detector, read 8 November 2026).
- Choose QuillBot ifyou want the check inside Chrome, Edge, Word, macOS or a phone keyboard: six surfaces against none stated for Scribbr (quillbot.com/premium, read 8 November 2026).
- Choose QuillBot ifyou want a result that distinguishes "Generated and refined by AI" from "Written by a human and refined by AI": Scribbr returns one percentage (quillbot.com/blog, read 8 November 2026).
- Choose Scribbr ifyour text is under 80 words: QuillBot states a minimum of 80 words per scan and Scribbr states no minimum (quillbot.com/ai-content-detector, read 8 November 2026).
- Choose QuillBot ifyou want the vendor that entered a public leaderboard: its RAID entry of 30 January 2025 is readable in the submissions repository, where Scribbr has none (github.com/liamdugan/raid, read 9 November 2026).
How does the evidence compare, tool by tool?
Scribbr
- Register ID
- AIDI-D-0009
- Study records
- 1 in the index: Walters 2023
- Shared with QuillBot
- 0
- Vendor accuracy claim
- 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.
- Free tier
- Unlimited free AI checks, no sign-up required
- Languages
- 1 stated
QuillBot
- Register ID
- AIDI-D-0007
- Study records
- 2 in the index: Kar 2024, Alshammari and Rao 2025
- Shared with Scribbr
- 0
- Vendor accuracy claim
- Detect AI text reliably with a 99% detection rate, according to independent evaluations from RAID.
- Free tier
- Up to 1,200 words per scan, up to 6 scans per day, 1 free explainer card; no sign-up for scans under 1,200 words
- Languages
- 6 stated
How this comparison is built
- Fields
- The 14 fields of every card, in card order
- Shared study records
- 0
- Fields checked
- 8 November 2026
- Records in the studies index
- 35 records
Both columns are drawn from the same 14 fields in the index data file, read on 8 November 2026 from the vendor page recorded on each card, and from the studies index, where each result is copied as the paper reports the figure, with the base stated. The ownership field of both cards cites the same sentence on scribbr.com, and the comparison states that neither vendor page says whether the two detectors share a model, because the index records what the pages say and not what a shared parent implies. No record ran both tools, so the evidence table lists each record with "Not tested" in the other column, QuillBot's leaderboard entry in a row labelled as an entry rather than a study, and each vendor's own statement in a labelled row. The rules, the recheck schedule (next pass 8 December 2026) and the correction route are on the methodology page; the false positive rate ranking sorts Scribbr on the Walters 2023 figure and lists QuillBot among the cards with no rate.
Where each figure comes from
Values as each vendor states them on scribbr.com/ai-detector, scribbr.com/plagiarism-checker, scribbr.com/about-us, quillbot.com/ai-content-detector, quillbot.com/premium and the QuillBot detector blog post, all read 8 November 2026. An empty cell means the card has no published value for the field: Scribbr's detector page states no input limit, no API and no integrations; QuillBot publishes no API and no retention statement for the detector.
Questions about Scribbr and QuillBot
Are Scribbr and QuillBot the same company?
They are two brands of one group: Scribbr's about page says it is "a part of QuillBot, within the broader Learneo family of businesses", with LanguageTool as the third brand (scribbr.com/about-us, read 8 November 2026). Neither detector page says whether the two tools share a model.
Which has a measured false positive rate?
Scribbr: 2% of 42 human-written papers in Walters 2023 (De Gruyter 10.1515/opis-2022-0158, Table 4, read 8 November 2026). QuillBot's two records print displayed scores, not a rate, and its vendor page states no numeric false positive figure.
Did any study test both detectors on the same text?
No. Walters 2023 ran Scribbr and not QuillBot; Kar 2024 and Alshammari and Rao 2025 ran QuillBot and not Scribbr (Walters 2023, Kar 2024, Alshammari and Rao 2025).
Which is free without limits?
Scribbr: "Unlimited free AI checks, no sign-up required" (scribbr.com/ai-detector, read 8 November 2026). QuillBot's free tier is 1,200 words per scan and 6 scans a day; Premium at $8.33 a month billed annually removes the word limit (quillbot.com/premium).
Which supports more languages?
QuillBot names 6 and Scribbr 1 (quillbot.com/blog, scribbr.com/ai-detector, read 8 November 2026).
What does QuillBot's 99% claim rest on?
The detector page says "a 99% detection rate, according to independent evaluations from RAID", and the RAID leaderboard holds a vendor-submitted QuillBot entry of 30 January 2025 at 99.62% with 2,497 misses and AUROC 0.9962 (quillbot.com/ai-content-detector, read 8 November 2026; github.com/liamdugan/raid, read 9 November 2026). The entry is the vendor's own submission to a shared benchmark, not a paper, and the RAID 2024 paper itself did not test QuillBot.
Does either keep the text you paste?
Scribbr says "we do not store or share your data. Submissions will never be added to our content database" (scribbr.com/ai-detector, read 8 November 2026). QuillBot's detector page and the pages read carry no retention statement for the detector, so its card has no value in that field.
Sources and revisions
Sources
- Scribbr AI Detectorscribbr.com/ai-detector
- Scribbr plagiarism checker (premium prices)scribbr.com/plagiarism-checker
- Scribbr about (Learneo)scribbr.com/about-us
- QuillBot AI Detectorquillbot.com/ai-content-detector
- QuillBot Premiumquillbot.com/premium
- QuillBot detector blog post (languages, result bands)quillbot.com/blog/quillbot-tools/ai-detector
- Walters 2023degruyterbrill.com/document/doi/10.1515/o...
- Kar, Bansal, Modi and Singh 2024 (read 9 November 2026)doi.org/10.1177/02537176241247934
- Alshammari and Rao 2025 (read 9 November 2026)arxiv.org/abs/2507.17944
- RAID leaderboard submissions (read 9 November 2026)github.com/liamdugan/raid/tree/main/leade...
