Strong match
80–100% sentence similarity
Strong wording overlap. Check whether the passage is quoted, cited, licensed or needs revision.
Sentence-level source evidence
Plagiarism Checker
Paste text or upload a file to find strong and similar passages, review the similarity percentage and open the closest matching web source.
Text to checkEnglish
3,000 words max
Add a document to search for matches
Paste text, upload TXT, PDF or DOCX, or start typing.
Need a known match?
- Strong + similar matches
- Linked web sources
- TXT, PDF + DOCX
- Evidence, not a verdict
How it works
How this plagiarism checker works
A useful report shows the wording and the source behind every flag, not just one percentage.
- 1
Add a meaningful sample
Paste text or upload a TXT, PDF or DOCX file. Each scan accepts up to 3,000 words.
- 2
Search for overlap
Your document is split into sentences and compared with candidate pages found across the public web.
- 3
Inspect the evidence
Select a highlighted passage to compare wording, open the source or copy an APA, MLA or Chicago citation.
Reading the report
How to read the similarity report
Sentence similarity describes textual overlap. It does not know whether a quotation is licensed, a citation is correct or an author intended to deceive.
Similar sentences count at half weight in the overall score. Strong matches count at full weight.
Similar wording
60–79% sentence similarity
Related structure or phrasing. Read both passages because shared facts and conventional language can raise similarity.
No close match
Below the review threshold
No close source was returned from this search. It does not prove the passage has never appeared elsewhere.
What you get
What every plagiarism check includes
Each scan returns the complete plagiarism report, with sources and citations included.
Sentence-level matches
Every sentence is classified as a strong match, similar wording or no close match, so you can see exactly which lines need attention.
Linked web sources
Each flagged passage links to the closest page found on the public web. Read both texts side by side instead of trusting a bare score.
A similarity percentage you can audit
The overall score is word-weighted: strong matches count in full and similar wording counts at half. The report shows how the number was built.
Scan exclusions
Ignore quoted passages or stop before a bibliography. These exclusions change the exact text sent for the scan.
Citations in one click
Copy an APA, MLA or Chicago citation for any matched source directly from the report.
Paste or upload files
Check pasted text or TXT, PDF and DOCX files up to 5 MB. File text is read in your browser before anything is sent.
Know what you are checking for
What counts as plagiarism
Plagiarism is presenting someone else’s words or ideas as your own without credit. It covers more than word-for-word copying, and several forms appear in drafts assembled carelessly. Academic integrity policies may treat them in the same way.
Direct copying
Text pasted from a source without quotation marks or credit. This is the most obvious form and the one a plagiarism checker flags most reliably.
Paraphrasing without credit
Rewording a passage while keeping its structure and ideas, then presenting it as original work. A citation fixes it. Silence does not.
Mosaic plagiarism
Fragments from several sources stitched together with small edits between them. Individual sentences can look harmless while the section as a whole is borrowed.
Self-plagiarism
Reusing your own earlier submission or publication without disclosure. Many institutions and journals treat this as misconduct even though the words are yours.
Accidental plagiarism
A missing citation, a paraphrase that stayed too close or a quotation without marks. Review flagged passages before you submit rather than after a report is filed.
Prevention
How to avoid plagiarism before you submit
Five habits that protect originality better than any score.
- 1
Keep a source list from the first draft
Most accidental plagiarism starts as a note without a URL or page number that later reads like an original sentence.
- 2
Quote exactly and cite
When the wording itself matters, use quotation marks, name the author and add the reference in the format your institution expects.
- 3
Paraphrase from memory, then compare
Close the source, write the idea in your own structure and check that your version did not drift back toward the original.
- 4
Cite your own earlier work
Reusing a paragraph from a previous paper needs the same disclosure as any outside source.
- 5
Run a plagiarism check before submission
A similarity percentage alone decides nothing. Open each flagged passage, confirm quotes and citations and rewrite what you cannot attribute.
Built for review
Who this plagiarism detector is for
Check the source before judging the writer.
Students and educators
Review citations and source use before submission without treating a similarity score as a misconduct verdict.
Editors and publishers
Triage contributed drafts, inspect the closest source and focus review time on passages with meaningful overlap.
Researchers
Catch missing attribution and distinguish a close textual match from a merely related idea or standard phrase.
Content and SEO teams
Screen articles for duplicate content before publishing and confirm that syndicated or licensed passages are labeled as the agreement requires.
FAQ
Plagiarism checker FAQ
Similarity is evidence to inspect. Context, citation, permission and policy determine what it means.
How does this plagiarism checker work?
The checker separates the submitted document into sentences, searches for candidate web sources, compares the closest text and classifies each sentence as a strong match, similar wording or no close match. The report links the closest source when one is available.
What are the plagiarism checker limits?
Each scan requires a signed-in account, accepts up to 3,000 words and uses one plagiarism credit for every two sentences, rounded up. The report includes the similarity percentage, sentence-level matches, linked sources and citation export.
What does the overall similarity score mean?
It is a word-weighted document score. Words in strong-match sentences contribute their full weight, while words in similar sentences contribute half. It is a review aid, not a probability that the author plagiarized.
What is a good similarity score?
There is no universal threshold. Institutions and publishers set their own limits. A low percentage can still hide one uncited paragraph, while a higher one can be entirely quoted and cited. Read the flagged passages instead of stopping at the number.
Will the result match Turnitin or my university checker?
Not exactly. Every plagiarism detector searches a different index, so percentages differ between tools. This checker searches the public web and shows the sources it used. It is a pre-submission review, not a prediction of an institutional report.
Can it catch paraphrased plagiarism?
Often, within limits. The similar-wording tier flags passages that keep the structure of a source with words swapped. A paraphrase that shares no meaningful wording with its source can pass a matching tool, which is one more reason citations matter more than scores.
Will quotations or bibliographies raise the score?
They can. Open Scan settings to ignore quoted passages or stop before a bibliography. Always review whether matching text is properly quoted and cited.
Which files can I upload?
You can upload TXT, PDF and DOCX files up to 5 MB. File text is read in your browser. Scanned PDFs without selectable text require OCR and are not supported yet.
Does plagiarism checking also detect AI writing?
No. Source overlap and AI authorship are different questions. Use the separate AI Detector for a sentence-level AI writing signal.
What happens to the text I submit?
Nothing is sent while you type. When you start a scan, the text after local quote or bibliography exclusions is sent to the plagiarism search service for processing. The result is saved to your private account history. Avoid submitting confidential material you are not allowed to share with a processing service.
Different questions, same document
Run the other checks on the same text
Source matching cannot identify AI writing, and an AI score says nothing about copied sources. Each tool answers one question.
Detecting AI
A sentence-level AI writing signal for the same text. Source overlap and AI authorship are different questions.
Fact Checker
Claim-level review that labels statements as supported, contradicted or uncertain, with sources.
AI Humanizer
Rewrites text with visible, reviewable edits so you can see exactly what changed.
Plagiarism Checker API
Run the same source-matching checks from your own product, pipeline or LMS integration.