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Crossref Similarity Check

crossref.org

From $3.33/mo Free plan WebAPI
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Spec score 8.4 #8 of 31 in Plagiarism Checkers

What it is

Crossref Similarity Check is a paid plagiarism-screening service for Crossref members. It compares submitted manuscripts with academic publications and general web content, using Turnitin’s iThenticate software. Reports provide a Similarity Score and highlight matching passages for editorial review. Crossref says the comparison database contains over 78 million full-text scholarly content items. Editors can submit manuscripts in iThenticate or through a manuscript system using the API, then receive an immediate report describing potential matches and overlap. Membership includes read-only database access, discounted checking fees, unlimited organizational users, 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 is $40 a year, representing 20% of the membership fee. Per-document checking is free for the first 100 documents yearly, then volume-tier charges apply to documents up to 25,000 words.

Spec sheet

Purpose
Similarity Check helps Crossref members detect potential plagiarism by comparing manuscripts with published academic and general web content.Read 9 Oct 2026 · crossref.org
Founded
2000Read 28 Sep 2026 · crossref.org
Access methods
Users can submit manuscripts through the iThenticate tool or through a manuscript submission system using an API.Read 9 Oct 2026 · crossref.org
Database
Crossref says the iThenticate database contains over 78 million full-text scholarly content items.Read 9 Oct 2026 · crossref.org
Eligibility
Participation requires Crossref membership, actively publishing DOI-assigned content, and including full-text URLs in metadata for Similarity Check.Read 9 Oct 2026 · crossref.org
Fee structure
The service charges an annual fee equal to 20% of the Crossref membership fee plus per-document checking fees, with volume discounts.Read 9 Oct 2026 · crossref.org
Indexing
Turnitin’s Content Intake System accesses Crossref metadata daily to collect members’ full-text URLs and index the linked content.Read 9 Oct 2026 · crossref.org
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.Read 9 Oct 2026 · crossref.org
Powered by
The service is powered by iThenticate text comparison software from Turnitin.Read 9 Oct 2026 · crossref.org
Provider
Crossref describes itself as a not-for-profit membership organisation that began in January 2000.Read 9 Oct 2026 · crossref.org
Regional availability
Crossref states that it can no longer offer Similarity Check to members based in Russia.Read 9 Oct 2026 · crossref.org
Service status
Crossref directs users to Turnitin’s service status page for real-time updates about performance and ongoing issues.Read 9 Oct 2026 · crossref.org
Similarity reports
iThenticate reports a Similarity Score and highlights matching text for editors to review.Read 9 Oct 2026 · crossref.org
Word limit
The published per-document price schedule applies to documents up to 25,000 words.Read 9 Oct 2026 · crossref.org
Workflow
Editors can upload a manuscript and receive an immediate report showing potential matches and how the paper overlaps with other work.Read 9 Oct 2026 · crossref.org

Plans and prices

Similarity Check per-document checking Free Invoiced annually in January for the previous year’s usage. 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 $40 a year Included in the annual membership fee invoice; prorated for the remainder of the calendar year when first joining. 20% of annual Crossref membership fee · fee depends on membership tier Read 9 Oct 2026 · crossref.org

Every Crossref Similarity Check plan and price →

Strong points and limits

Strong points

  • Academic and web source matching
  • Similarity scores with highlighted matches
  • API and web submission
  • PDF report export
  • Unlimited organizational user accounts

Limits

  • Crossref membership is required
  • No free plan
  • Unavailable to members based in Russia
  • Per-document fees after 100 yearly

Who it suits

It suits Crossref members publishing DOI-assigned content who need manuscript similarity reports. Editors and organizations needing API or web submission can use it.

Verdict

Crossref Similarity Check combines iThenticate comparison with Crossref membership features and API access. Eligibility requirements and usage-based fees matter before signing up.

Where Specifiction places it

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