Direct answer
You can check a Word document for plagiarism by uploading the .docx file to a similarity checker that compares it against web pages, journals, and previously submitted student papers. Microsoft Word's built-in Editor Similarity feature only searches Bing-indexed web content, so it will not catch matches against your university's paper repository [2]. For a report that mirrors what your instructor sees, upload the file to a check that uses the same detection engine as your institution and review the highlighted matches yourself [1][3].
Does Microsoft Word Have a Built-In Plagiarism Checker?
Microsoft Word does include a similarity tool, but its scope is narrower than most students assume. Editor's Similarity feature, available in Microsoft 365, compares your text against online sources and flags passages that may need a citation [2]. It is designed as a writing aid that prompts you to attribute sources, not as an academic-integrity report.
The critical limitation is the corpus it searches. Editor Similarity looks at Bing-indexed web content, so it cannot see paywalled journal articles, publisher databases, or the internal repository of student papers your university holds [2]. A document can pass Editor Similarity cleanly and still return a substantial match against a previously submitted essay from the same course.
Because the underlying index differs, the output is not comparable to an institutional Turnitin similarity report [2]. Treat Word's checker as a first-pass citation prompt, not as a final verdict on originality. If your assignment will be graded through Turnitin, a Word-only check leaves the most institution-specific risk unmeasured.
What Is the Best Way to Check a.docx File for Plagiarism Before Submitting?
The most reliable method is to check the draft with the same detection engine your institution uses, so the score you see reflects the score you would receive [3]. That means uploading the original .docx file rather than pasting plain text into a browser box, because the file format preserves your headings, in-text citations, and reference list as distinct elements [3]. When those elements are preserved, quotation marks and bibliographies can be recognised and excluded from the match percentage instead of inflating it [1].
Once you have the report, read it as a revision tool rather than a pass/fail grade. Open each highlighted match and check whether the passage is properly quoted and cited; where it is not, add the citation or rewrite the sentence in your own words [3]. Mechanical synonym-swapping is a common mistake — it changes surface wording while leaving the underlying structure of someone else's argument intact, which is exactly the pattern academic-integrity panels look for [3].
It also helps to know what the percentage actually represents before you panic. The similarity score is the proportion of your text that matched a source, and correctly cited quotations, common phrases, and standard terminology all count toward it [1]. Instructors can exclude quotes, bibliographies, and small matches from the calculation, which is one reason the number in your report may not equal the number in your instructor's view [1]. A high score is a signal to review specific passages, not proof of misconduct.
Finally, run the check early enough to act on it. Building a pre-submission check into your drafting schedule — a day or two before the deadline — leaves room to fix citations and re-check the revised file [3]. A check run an hour before submission tells you about a problem you no longer have time to solve.
Is It Safe to Upload My Word Document to an Online Plagiarism Checker?
Safety depends almost entirely on whether the service uses a repository. A repository check stores your submission in a student paper database so that future submissions are compared against it; a non-repository check does not add your file to that database [4]. Both can produce a useful report, but they affect your document differently after the fact.
This distinction explains a confusing student experience: a draft that scored low on a non-repository check can score higher when the same text is submitted through the institution, because the institutional submission is generally retained for comparison against later work [4]. Neither outcome is wrong — they are answers to different questions.
Before uploading anywhere, confirm three things about the service: how long files are kept, whether documents are shared with or sold to third-party databases, and whether you can delete your file from your account afterwards [4]. Avoid any checker that publishes uploaded papers or uses them as public content. A provider that states its retention and deletion policy plainly is a provider you can make an informed decision about [4].
Practical safeguards are simple. Keep the original file and upload a copy, strip any personal identifiers you do not need to share, and prefer a service that checks without adding your work to a shared database so your own draft cannot later match itself [4]. If your institution offers a formative or draft submission window, use it — that route keeps everything inside systems your university already governs [4].
Reading a similarity report is straightforward once you have one in front of you — the hard part is getting a report that matches what your instructor will see. turnitin0 gives you that preview: upload your .docx and receive a Turnitin AI detection report and a similarity report together, generated without adding your file to a shared student paper database, so you can fix the flagged passages before the real deadline.
※ Turnitin0.com - Actual Turnitin AI Report Cover, Score, Flag And Similarity Summary
FAQ
Does Microsoft Word check for plagiarism automatically?
No. Word's Editor Similarity feature is opt-in and only compares your text against Bing-indexed web sources, so it will not detect matches against your university's paper repository or paywalled journals [2]. You have to run it deliberately, and its results are not equivalent to an institutional similarity report [2].
What file types can I upload to a plagiarism checker?
Most checkers accept .docx, .pdf, and .txt. Uploading the original .docx is usually best because it preserves headings, in-text citations, and your reference list as separate elements that can be excluded from the match percentage [1][3].
What similarity percentage is too high?
There is no universal threshold. The score is simply the share of your text that matched a source, and correctly cited quotations and common phrases count toward it [1]. Instructors can exclude quotes, bibliography, and small matches, so review the highlighted passages rather than chasing a number [1].
Will checking my own draft get me flagged for self-plagiarism?
Only if the checker adds your file to a shared repository. A non-repository check does not store your submission in the student paper database, so your own draft cannot later match itself [4]. Confirm the service's retention and deletion policy before you upload [4].
Can I check a Word document without uploading it?
Not against a paper repository. Offline tools and Word's own similarity feature can only compare against web content they can index, which excludes institutional repositories and subscription databases [2]. Any check that claims to match student papers requires the document to be processed by that system [4].