What is iThenticate and How Does It Work? A Complete Guide for Researchers
When you submit a manuscript to an academic journal, one of the first things that happens — often before a human editor even reads your abstract — is an automated iThenticate check. Understanding how this tool works, what it compares your manuscript against, and how to interpret the report is essential preparation for journal submission.
What is iThenticate?
iThenticate is a plagiarism and similarity detection software developed by Turnitin LLC (the same company that makes Turnitin for students). It was specifically designed for professional and academic publishing — not for educational institutions. As of 2026, it is used by over 1,000 publishers and research organizations worldwide.
What Does iThenticate Check Against?
| Database | Content | Size |
|---|---|---|
| CrossRef | Published journal articles with DOIs | 150M+ documents |
| Internet archive | Web pages, blogs, online content | 60B+ pages |
| Preprint servers | arXiv, bioRxiv, SSRN, ResearchGate | 5M+ preprints |
| ProQuest | Dissertations and theses | 5M+ documents |
| Previously submitted manuscripts | Papers submitted through iThenticate | Proprietary |
How iThenticate Calculates the Similarity Score
iThenticate breaks your manuscript into overlapping text strings (typically 8+ consecutive words) and searches for matches in its database. The similarity percentage = (number of matching words) / (total words in manuscript) × 100. This calculation can be configured by publishers to exclude references, quotations, and small matches.
How to Read an iThenticate Report
The report shows your overall similarity percentage and a color-coded breakdown by source. Each matching passage is highlighted in the document, with the source identified in the sidebar. Key things to look for:
- Overall percentage: Your starting point — but not the final judgment
- Top matching sources: Which sources contribute most to your score?
- Match distribution: Are matches spread across many sources or concentrated?
- Match location: Body text matches are more concerning than reference matches
- Match length: Long continuous matches are more concerning than scattered short ones
iThenticate vs Turnitin: Key Differences
| Feature | iThenticate | Turnitin |
|---|---|---|
| Primary use | Academic publishing | Education (student papers) |
| Database focus | Published research, preprints | Student papers, internet |
| Access | Per-document or institutional subscription | Institutional only |
| Cost per check | ~$5–25 per document | Via institution |
| Used by journals | Yes — industry standard | No |
How to Access iThenticate Before Submission
- Direct purchase: ithenticate.com — pay per document (~$5–25)
- Institutional access: Many universities provide iThenticate to researchers — check with your library
- ScholarAI estimate: Get a similarity estimate before committing to a paid check
Conclusion
iThenticate is the gatekeeper for Q1 journal submission. Understanding how it calculates scores, what it checks against, and how to read the report transforms it from a scary obstacle into a manageable pre-submission tool. Check your manuscript before submission, not after rejection.
Estimate Your iThenticate Score Before Paying
ScholarAI gives you a similarity estimate and flags high-risk passages — so you know what to fix before running your paid iThenticate check.
Get My Similarity Estimate Free →