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Crossref Similarity Check
What it is
Crossref Similarity Check helps eligible Crossref members find potential plagiarism by comparing manuscripts with published academic and general web content. Turnitin’s iThenticate software powers the service. Reports show a Similarity Score and highlight matching text for editors to assess; the comparison database contains over 78 million full-text scholarly content items, according to Crossref. Users can submit manuscripts in iThenticate or through a manuscript submission system using an API. Members receive read-only access to database full text, discounted checking fees, unlimited organizational user accounts, and enhanced text matches in Document Viewer. Participation requires Crossref membership, active publication of DOI-assigned content, and full-text URLs in metadata. The annual service fee equals 20% of the Crossref membership fee and depends on membership tier. Per-document charges are invoiced annually; the first 100 documents each year are free for documents up to 25,000 words, followed by volume-tier rates. Crossref states that the service is unavailable to members based in Russia.
For and against
For
- Reports include a Similarity Score and highlighted matches.
- Manuscripts can be submitted through an API.
- First 100 documents each year are free.
- Members receive unlimited organizational user accounts.
Against
- Crossref membership is required.
- Annual service fee is 20% of the membership fee.
- Members based in Russia cannot use the service.
The verdict
Similarity Check provides manuscript matching and reports for eligible Crossref members, with both annual and per-document fees. Eligibility requirements and the stated regional restriction are important to consider before joining.
Who it suits
It suits Crossref members that actively publish DOI-assigned content and include full-text URLs in metadata, particularly editorial teams reviewing manuscripts.
Plans and prices
Similarity Check per-document checking
First 100 documents per year free · up to 25,000 words per document · subsequent rates are $0.75, $0.65, $0.55, $0.45, $0.30, or $0.25 per document by annual volume tier
Read 9 Oct 2026 · crossref.org
Similarity Check annual service fee
20% of annual Crossref membership fee · fee depends on membership tier
Read 9 Oct 2026 · crossref.org
On the record
- Access methods
- Users can submit manuscripts through the iThenticate tool or through a manuscript submission system using an API.crossref.org · read 9 Oct 2026
- Database
- Crossref says the iThenticate database contains over 78 million full-text scholarly content items.crossref.org · read 9 Oct 2026
- Eligibility
- Participation requires Crossref membership, actively publishing DOI-assigned content, and including full-text URLs in metadata for Similarity Check.crossref.org · read 9 Oct 2026
- Fee structure
- The service charges an annual fee equal to 20% of the Crossref membership fee plus per-document checking fees, with volume discounts.crossref.org · read 9 Oct 2026
- Indexing
- Turnitin’s Content Intake System accesses Crossref metadata daily to collect members’ full-text URLs and index the linked content.crossref.org · read 9 Oct 2026
- Member features
- Similarity Check members receive read-only access to full text in the comparison database, discounted checking fees, unlimited organizational user accounts, and enhanced text matches in Document Viewer.crossref.org · read 9 Oct 2026
- Powered by
- The service is powered by iThenticate text comparison software from Turnitin.crossref.org · read 9 Oct 2026
- Provider
- Crossref describes itself as a not-for-profit membership organisation that began in January 2000.crossref.org · read 9 Oct 2026
- Purpose
- Similarity Check helps Crossref members detect potential plagiarism by comparing manuscripts with published academic and general web content.crossref.org · read 9 Oct 2026
- Regional availability
- Crossref states that it can no longer offer Similarity Check to members based in Russia.crossref.org · read 9 Oct 2026
- Service status
- Crossref directs users to Turnitin’s service status page for real-time updates about performance and ongoing issues.crossref.org · read 9 Oct 2026
- Similarity reports
- iThenticate reports a Similarity Score and highlights matching text for editors to review.crossref.org · read 9 Oct 2026
- Word limit
- The published per-document price schedule applies to documents up to 25,000 words.crossref.org · read 9 Oct 2026
- Workflow
- Editors can upload a manuscript and receive an immediate report showing potential matches and how the paper overlaps with other work.crossref.org · read 9 Oct 2026
