Crossref Similarity Check
Crossref Similarity Check helps eligible Crossref members identify potential plagiarism by comparing manuscripts with published academic and general web cont…
What Crossref Similarity Check is
Crossref Similarity Check helps eligible Crossref members identify potential plagiarism by comparing manuscripts with published academic and general web content. Turnitin’s iThenticate software powers the comparison, and reports provide a Similarity Score with matching text highlighted for editors to review. Crossref says the database includes over 78 million full-text scholarly content items. Manuscripts can be submitted through iThenticate or through a manuscript submission system using an API. 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. Participation requires Crossref membership, active publication of DOI-assigned content, and full-text URLs in metadata. The annual service fee is 20% of the Crossref membership fee, depending on membership tier. Per-document charges are invoiced annually; the first 100 documents per year are free for documents up to 25,000 words, with volume-tier rates applying thereafter. Crossref says the service is unavailable to members based in Russia.
Good
- Compares against academic and general web content.
- Reports show a Similarity Score and highlighted matches.
- API submission is supported.
- First 100 documents per year are free.
- Members receive unlimited organizational user accounts.
Watch out
- Requires Crossref membership and qualifying publication activity.
- Annual service fee is 20% of the membership fee.
- Per-document fees apply after the first 100.
- Unavailable to members based in Russia.
Who it suits
Similarity Check is for Crossref members that actively publish DOI-assigned content and include full-text URLs in metadata. It suits editorial teams reviewing manuscript matches through iThenticate or an API-enabled submission system.
Verdict
Similarity Check provides manuscript matching and review reports to eligible Crossref members. Its costs combine a membership-based annual fee and per-document charges after the annual free allowance.
Plans and prices
From Crossref Similarity Check's own pricing page, checked 9 Oct 2026.
| Plan | Price | What it gives you |
|---|---|---|
| Similarity Check per-document checking | Free | 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 · Invoiced annually in January for the previous year’s usage. |
| Similarity Check annual service fee | $40 a year | 20% of annual Crossref membership fee · fee depends on membership tier · Included in the annual membership fee invoice; prorated for the remainder of the calendar year when first joining. |
The facts
Each one read from Crossref Similarity Check's own pages, with the date it was checked.
What it does
- Access methods
- Users can submit manuscripts through the iThenticate tool or through a manuscript submission system using an API.checked 9 Oct 2026
- Database
- Crossref says the iThenticate database contains over 78 million full-text scholarly content items.checked 9 Oct 2026
- Eligibility
- Participation requires Crossref membership, actively publishing DOI-assigned content, and including full-text URLs in metadata for Similarity Check.checked 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.checked 9 Oct 2026
- Indexing
- Turnitin’s Content Intake System accesses Crossref metadata daily to collect members’ full-text URLs and index the linked content.checked 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.checked 9 Oct 2026
- Powered by
- The service is powered by iThenticate text comparison software from Turnitin.checked 9 Oct 2026
- Provider
- Crossref describes itself as a not-for-profit membership organisation that began in January 2000.checked 9 Oct 2026
- Purpose
- Similarity Check helps Crossref members detect potential plagiarism by comparing manuscripts with published academic and general web content.checked 9 Oct 2026
- Regional availability
- Crossref states that it can no longer offer Similarity Check to members based in Russia.checked 9 Oct 2026
- Service status
- Crossref directs users to Turnitin’s service status page for real-time updates about performance and ongoing issues.checked 9 Oct 2026
- Similarity reports
- iThenticate reports a Similarity Score and highlights matching text for editors to review.checked 9 Oct 2026
- Word limit
- The published per-document price schedule applies to documents up to 25,000 words.checked 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.checked 9 Oct 2026
The company
- Founded
- 2000checked 28 Sep 2026
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