Scribbr vs Turnitin AI detection: the 14 fields and the study results side by side
Turnitin carries 5 study records in the index and Scribbr 1, and that one record tested both on the same documents: Walters 2023, where Turnitin classified 100% of 126 documents correctly and Scribbr 88%, with 0 of 42 human-written papers flagged by Turnitin and 2% by Scribbr (De Gruyter 10.1515/opis-2022-0158, Table 4, read 8 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, so the comparison rests on what each company publishes and what outside researchers measured.
Updated Fields checked 8 November 2026
Short answer
Scribbr's detector is free, unlimited and open to anyone without an account; Turnitin's AI writing detection has no public price and is licensed to institutions through Turnitin Originality, with results visible to instructors and administrators only (scribbr.com/ai-detector, guides.turnitin.com, read 8 November 2026). In Walters 2023, the one study that ran both, Turnitin scored 100% of 126 documents and Scribbr 88%, with Scribbr at 69% on the 42 GPT-4 papers; Turnitin flagged 0 of 42 human papers and Scribbr 2% (De Gruyter 10.1515/opis-2022-0158, Table 4). Scribbr states English only and no storage of submissions; Turnitin states 7 languages, a 300-word minimum and a 30,000-word maximum, and keeps AI results inside the Similarity Report. No detector score should be the only evidence in a misconduct or hiring decision.
How do Scribbr and Turnitin compare on the 14 fields?
| Field | Scribbr | Turnitin |
|---|---|---|
| 1. Name, vendor, official domain | Scribbr's AI Detector, Scribbr, scribbr.com | Turnitin AI writing detection, Turnitin, LLC, turnitin.com |
| 2. Modalities detected | text | text |
| 3. Generators covered | ChatGPT, Gemini, Copilot, GPT2, GPT3, GPT3.5, GPT4 (experimental in the free tool, supported in Premium) | 33 named models from Amazon Nova 2 Lite and Claude-3-Haiku to GPT-5.4-pro, Grok-4.1, Llama-4-Maverick-17b and Mistral-large-3; Spanish model GPT-3.5 and GPT-4; Japanese model GPT-4 (0613), GPT-4o, GPT-4o-mini |
| 4. Languages supported | 1: English | 7: English, Spanish, Japanese, Modern Arabic, Dutch, German, Turkish |
| 5. Input limits | At least 300 words of prose in a long-form format and no more than 30,000 words; file under 100 MB; .docx, .pdf, .txt, .rtf; lists, headers, references, tables, formulas and code excluded from scoring | |
| 6. Free tier | Unlimited free AI checks, no sign-up required | None: AI writing detection is only available to customers that license Turnitin Originality, or the AI writing add-on for iThenticate 2.0 |
| 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 | No public plans: institutional licence through Turnitin Originality; price by sales |
| 8. API | None published | |
| 9. Integrations | LMS (Moodle, Blackboard, Canvas and others) through the Similarity Report, with no AI indicator embedded in the LMS interface; Microsoft Teams through Feedback Studio only | |
| 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" | No overall accuracy figure; document false positive rate "under 1% for documents with over 20% of AI writing", validated on over 700,000 pre-ChatGPT academic papers before each release; ELL writers 0.014 and native English writers 0.013 false positive rate in the vendor's own research |
| 11. Independent studies | 1 record: Walters 2023 | 4 independent records (Weber-Wulff 2023, Walters 2023, Perkins 2024, Van Vlasselaer 2026) plus the vendor statements record |
| 12. Data retention and privacy statement | "we do not store or share your data. Submissions will never be added to our content database" | No separate repository for AI writing detection; customers choose whether student papers enter the repository; AI results retained as part of the similarity report; full deletion of submissions on request, no partial deletion of the AI component |
| 13. Launch year and ownership | Not stated; part of QuillBot, within the Learneo family of businesses | 2023; Turnitin, LLC, no parent company stated on the pages read |
| 14. Rankings the card appears in | Independently tested, false positive rate, languages, data retention | Independently tested, false positive rate, free tiers, languages, input limits, adversarial robustness, false negative rate, platform integrations, file types |
Which studies tested both Scribbr and Turnitin?
One record. 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, 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). The author notes that the student papers could have been used to train Turnitin's detector, a caveat that applies to Turnitin's row and not to Scribbr's. Turnitin's other records tested it without Scribbr: Weber-Wulff 2023, Perkins 2024, Van Vlasselaer 2026 and the vendor's own statements in the Turnitin claims record. No other indexed record tested Scribbr.
| Source | Scribbr | Turnitin |
|---|---|---|
| Walters 2023, share of 126 documents correct (Table 4) | 88% correct, 11% incorrect, 1% uncertain | 100% correct, 0 incorrect, 0 uncertain |
| Walters 2023, 42 GPT-3.5 papers | 100% correct | 100% correct |
| Walters 2023, 42 GPT-4 papers | 69% correct | 100% correct |
| Walters 2023, 42 human-written papers | 95% correct, 2% incorrect (false positive rate 2%) | 100% correct, 0 false positives |
| Weber-Wulff 2023, 54 documents | Not tested | 41 of 54 correct (76%, rank 1 of 14); 0 false accusations in 18 human documents; 10 of 36 AI documents undetected, all among edited or paraphrased texts |
| Perkins 2024, 114 samples | Not tested | Baseline mean accuracy 61% (rank 2 of 7); 50% on unmodified AI text falling to 7.9% after adversarial techniques; 0 false accusations in 10; 88 of 104 AI samples undetected |
| Van Vlasselaer 2026, 160 papers | Not tested | All 40 fully AI papers from ChatGPT Deep Research scored under 20%; 60.0% on 40 hybrid and 50.0% on 40 humanised papers; all 40 human papers correct |
| Turnitin claims record, vendor statements 2023 to 2026 | Document false positive rate under 1% for documents with over 20% AI writing on 800,000 (2023) and over 700,000 (current FAQ) pre-ChatGPT papers; sentence-level false positive rate about 4% (2023); no true positive rate or third-party audit published | |
| 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) |
Results as each study reports them: De Gruyter 10.1515/opis-2022-0158, arXiv 2306.15666, DOI 10.1186/s41239-024-00487-w, DOI 10.1007/s40979-026-00226-w, read 8 and 9 November 2026. "Not tested" means the paper did not run that tool.
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 | |
| Turnitin AI writing detection | No public price | No public price | Licensed with Turnitin Originality, or as the AI writing add-on for iThenticate 2.0; Similarity, Feedback Studio and Originality Check customers are told to speak to their account manager | 8 November 2026 |
Prices in USD as shown on scribbr.com/ai-detector and scribbr.com/plagiarism-checker, checked 8 November 2026; Scribbr sells per check, not by subscription, so a 12-month figure depends on how many documents are checked. Turnitin publishes no price for AI writing detection on any page read (guides.turnitin.com, read 8 November 2026).
One of the comparisons in the compare hub. The cards are Scribbr and Turnitin, and the home board answers which AI detectors exist and who has tested them? A student who wants to know what the institutional tool will say about a draft is the reader this pair is written for, and the one shared study is the only place the two were scored on the same papers.
Which card fits which reader?
- Choose Scribbr ifyou are a student checking your own draft before submission: unlimited free checks, no account, and a written no-storage line (scribbr.com/ai-detector, read 8 November 2026). Turnitin's results are visible to instructors and administrators only.
- Choose Turnitin ifyou are an institution that already licenses Turnitin Originality and wants the AI indicator inside the Similarity Report through Canvas, Moodle or Blackboard (guides.turnitin.com, read 8 November 2026).
- Choose Turnitin ifGPT-4 text is what you check: in Walters 2023 it scored 100% on 42 GPT-4 papers against Scribbr's 69% (De Gruyter, Table 4).
- Choose Scribbr ifyour text is under 300 words: Turnitin does not process documents with fewer than 300 words of prose, and Scribbr states no minimum (guides.turnitin.com, read 8 November 2026).
- Choose Turnitin ifyour submissions are in Spanish, Japanese, Arabic, Dutch, German or Turkish: Scribbr states English only (guides.turnitin.com, scribbr.com/ai-detector, read 8 November 2026).
- Choose Scribbr ifyou want the vendor that publishes its own ceiling: its page declines to guarantee any accuracy figure and reports 84% as the highest it found in any tool, where Turnitin publishes no overall accuracy figure at all (scribbr.com/ai-detector, read 8 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 Turnitin
- 1: Walters 2023
- 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
Turnitin
- Register ID
- AIDI-D-0002
- Study records
- 5 in the index: Weber-Wulff 2023, Walters 2023, Perkins 2024, Van Vlasselaer 2026, Turnitin claims
- Shared with Scribbr
- 1: Walters 2023
- Vendor accuracy claim
- None published
- Free tier
- None. AI writing detection is only available to customers that license Turnitin Originality (or the AI writing add-on for iThenticate 2.0).
- Languages
- 7 stated
How this comparison is built
- Fields
- The 14 fields of every card, in card order
- Shared study records
- 1: Walters 2023
- 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. Walters 2023 is the one record that ran both tools on the same documents, so its rows sit first in the evidence table; the single-tool records follow with "Not tested" in the other column, and each vendor's own statements sit in labelled rows. 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 both cards on the Walters 2023 figures used in the first sentence.
Where each figure comes from
Values as each vendor states them on scribbr.com/ai-detector, scribbr.com/plagiarism-checker, scribbr.com/about-us, the Turnitin AI writing detection FAQs and turnitin.com/solutions/topics/ai-writing, 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.
Questions about Scribbr and Turnitin
Which study tested both Scribbr and Turnitin?
Walters 2023, on 126 documents: Turnitin 100% correct with 0 false positives in 42 human papers, Scribbr 88% correct with 2% of the human papers flagged (De Gruyter 10.1515/opis-2022-0158, Table 4, read 8 November 2026).
Will Scribbr's score match Turnitin's?
Not on the one shared sample. Scribbr caught 69% of 42 GPT-4 papers and Turnitin 100%, so 13 papers Turnitin flagged passed Scribbr's free check (De Gruyter, Table 4). The author also notes the papers could have been in Turnitin's training data.
Which has the lower false positive rate?
Turnitin: 0 of 42 in Walters 2023, 0 of 18 in Weber-Wulff 2023, 0 of 10 in Perkins 2024 and 0 of 40 in Van Vlasselaer 2026; Scribbr's one measured rate is 2% of 42 (De Gruyter, arXiv 2306.15666). Turnitin's own under-1% figure is a vendor statement.
Can a student use Turnitin's AI detector?
Not directly. Only instructors and administrators see the indicator, and the feature is licensed to institutions through Turnitin Originality (guides.turnitin.com, read 8 November 2026). Scribbr's check is open to anyone.
Does Scribbr keep the text you paste?
The detector page 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). Turnitin keeps AI results inside the Similarity Report and lets institutions choose whether papers enter the repository.
Which supports more languages?
Turnitin names 7 and Scribbr 1 (guides.turnitin.com, scribbr.com/ai-detector, read 8 November 2026).
What does Scribbr's premium check cost?
$19.95, $29.95 or $39.95 per document by length, bundled with a premium plagiarism check and unlimited rechecks; there is no detector subscription (scribbr.com/plagiarism-checker, checked 8 November 2026). Turnitin publishes no price.
Sources and revisions
Sources
- Scribbr AI Detectorscribbr.com/ai-detector
- Scribbr plagiarism checker (premium prices)scribbr.com/plagiarism-checker
- Scribbr aboutscribbr.com/about-us
- Turnitin AI writing detection FAQsguides.turnitin.com/hc/en-us/articles/284...
- Turnitin AI writing pageturnitin.com/solutions/topics/ai-writing
- Walters 2023degruyterbrill.com/document/doi/10.1515/o...
- Weber-Wulff et al. 2023arxiv.org/pdf/2306.15666
- Perkins et al. 2024doi.org/10.1186/s41239-024-00487-w
- Van Vlasselaer 2026 (read 9 November 2026)doi.org/10.1007/s40979-026-00226-w
