Scribbr vs Turnitin: AI detector comparison
A side by side look at pricing, methodology, language support and best-fit use case. Every claim on this page is linked to a source at the bottom.
Last updated . Reviewed by IsItAI Editorial.
At a glance
Scribbr
Netherlands, 2012 (AI detector 2023)Student-focused, integrated with Scribbr's plagiarism and citation tools.
- Pricing
- Pay-per-check from $9.95
- Free tier
- 1.2k words free
- API
- No
- Languages
- 4
Turnitin
US, 1998 (AI detection added 2023)Institutional plagiarism and AI detection bundled into LMS workflows.
- Pricing
- Institution-licensed, around $3 per student/year
- Free tier
- No free tier (institutional only)
- API
- No
- Languages
- 30
Side by side
| Feature | Scribbr | Turnitin |
|---|---|---|
| Free tier | 1.2k words free | No free tier (institutional only) |
| Starting price | Pay-per-check from $9.95 | Institution-licensed, around $3 per student/year |
| Cost per 1k words | $0.30 | Not directly comparable |
| API available | No | No |
| Languages supported | 4 | 30 |
| Founded | 2012 (AI detector 2023) | 1998 (AI detection added 2023) |
| Country | Netherlands | US |
| Primary audience | Students and dissertation writers | Schools and universities at institutional scale |
| Best for | Students already using Scribbr for proofreading or citations | Universities and schools that already license Turnitin for plagiarism |
| Known weakness | Pay-per-check pricing gets expensive fast and there is no API | Not available to individual students or teachers, no public methodology |
How each tool works
Scribbr
Method: Detector white-labelled on top of Turnitin's underlying classifier per Scribbr's own published documentation.
Data handling: EU hosted. Submissions retained per Scribbr's published policy.
Turnitin
Method: Classifier layered onto the existing plagiarism similarity engine. Methodology not published in peer-reviewed venues.
Data handling: Stored in institutional Turnitin repository per the school's licence agreement.
How accurate are AI detectors? What the research says
Two findings from independent academic research apply to almost every detector on this list, including Scribbr and Turnitin.
1. False positives on non-native English writers. Liang et al. (Stanford, 2023) found that GPT detectors flagged over half of TOEFL essays written by non-native English speakers as AI-generated, while flagging almost none of the essays from US students. If your use case involves non-native English writers, never treat a detector verdict as proof on its own.
2. Paraphrasing reliably defeats classifiers. Sadasivan et al. (Maryland, 2023) showed that running AI output through a paraphraser drops detection performance close to chance. Both Scribbr and Turnitin are vulnerable to this.
For a deeper breakdown of how accuracy claims hold up across 2026 testing, see our guide to how accurate AI detectors actually are in 2026.
Where Scribbr wins
- Available to individual students with no institutional licence. Turnitin is sold to institutions only and cannot be bought by an individual.
- Pay-per-check from $9.95 with no subscription, plus a 1,200-word free allowance, useful for a one-off dissertation check.
- Bundled with Scribbr's plagiarism checker, citation generator and proofreading service for students.
Where Turnitin wins
- Integrated into the LMS and grading workflow most universities already run, so AI flags sit beside the existing similarity report.
- Wider language coverage at 30 languages versus 4.
- Institutional per-student pricing (around $3 per student per year) scales across a whole cohort far more cheaply than per-check fees.
Which one should you pick, Scribbr or Turnitin?
These two share an engine: Scribbr white-labels Turnitin's classifier per Scribbr's own documentation, so the underlying AI score is essentially the same. Pick Scribbr if you are an individual student who cannot access Turnitin and want a one-off check with citations and proofreading alongside. Pick Turnitin if your institution already licenses it and you want AI flags inside the same workflow as plagiarism. Vanderbilt University publicly disabled Turnitin's AI detector in 2023 over accuracy concerns, so treat the shared score as a screening signal, not proof.
Frequently asked questions
Is Scribbr free?
1.2k words free
Is Turnitin free?
No free tier (institutional only)
Can either tool be fooled by paraphrasing?
Yes. Sadasivan et al. (2023) demonstrated that paraphrasing reliably defeats most AI classifiers. Treat any detector verdict as a screening signal, not proof.
Are AI detectors fair to non-native English writers?
Independent research (Liang et al. 2023) found high false-positive rates for non-native English writing. Always combine a detector signal with other evidence, never use it as a sole basis for an academic or hiring decision.
Which one should I pick if I have to choose one, Scribbr or Turnitin?
These two share an engine: Scribbr white-labels Turnitin's classifier per Scribbr's own documentation, so the underlying AI score is essentially the same. Pick Scribbr if you are an individual student who cannot access Turnitin and want a one-off check with citations and proofreading alongside. Pick Turnitin if your institution already licenses it and you want AI flags inside the same workflow as plagiarism. Vanderbilt University publicly disabled Turnitin's AI detector in 2023 over accuracy concerns, so treat the shared score as a screening signal, not proof.
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Sources and further reading
- Scribbr AI detector
- Scribbr published comparison of AI detectors
- Turnitin AI writing detection page
- Vanderbilt University guidance on disabling Turnitin's AI detector (2023)
- Liang et al. (Stanford, 2023): GPT detectors are biased against non-native English writers
- Sadasivan et al. (2023): Can AI-generated text be reliably detected?