Attribution, checked before it matters
Plagiarism Checker: Find Source Overlap Before You Submit
Every match is a question. Answer it before your reader asks.
Scan a passage for wording that overlaps with published sources, then decide whether to quote, cite, or rewrite.
- Runs in GPTHumanizer’s checker
- 100–100,000 characters per scan
- Match-by-match review
Potential source matches will appear after the live check. Compare each result with its source before deciding what to change.
Check Plagiarism opens your passage in GPTHumanizer’s plagiarism checker, where the scan runs (100–100,000 characters). Full match reports there require a paid GPTHumanizer plan.
What a similarity check finds
Overlap is common. Unattributed overlap is the problem.
Most drafts share some wording with existing sources—quotations, standard phrases, names of laws and theories. The check helps you separate the matches that need attention from the ones that do not.
Quotations without marks
Wording copied from a source but missing quotation marks. Even with a citation, it reads as your own phrasing until the marks are added.
Close paraphrases
Sentences that follow a source’s structure with a few words swapped. These usually need either a genuine rewrite or a direct quotation.
Missing citations
Ideas, data, or arguments taken from a source with no reference. The fix is attribution, not rewording.
How to check
A plagiarism check that ends in better attribution
- 01
Paste the passage
Include the sections you are least sure about—the literature review, the background, the paragraphs drafted from notes.
- 02
Run the scan
Check Plagiarism carries the passage to the plagiarism checker and starts the scan there.
- 03
Open each source
Compare your sentence with the matched source in context. Decide whether it is a quote, a paraphrase, or shared common wording.
- 04
Fix and keep records
Add quotation marks and citations where needed, then keep the version you checked alongside the final file.
Reading the matches
Decide what each match needs.
A similarity percentage summarises the scan; the individual matches are where the decisions are made.
A direct quotation
Keep it if you need the exact words. Add quotation marks, cite the source, and make sure the quote is accurate.
A close paraphrase
Rewrite it from your understanding of the idea, not by swapping words—or quote it directly. Cite the source either way.
Common or technical phrasing
Standard terms, titles, and set phrases often match many sources. These usually need no change, but read them in context.
Your own earlier work
Reusing your previous writing can still require citation or permission. Check the rules for the work you are submitting.
Know the limits
What a plagiarism check cannot tell you.
It is not your school’s report
This is an independent scan, not a Turnitin report. Institutions use different databases, settings, and review processes.
Coverage varies
No scanner sees every document. Paywalled articles, private submissions, and very recent material may not be searchable.
It does not detect AI writing
Similarity and AI detection measure different things. Use the ChatGPT detector if you also want an AI-writing assessment.
It does not judge intent
A match shows overlap. Whether that overlap is acceptable depends on attribution, the assignment, and the people reviewing the work.
Frequently asked questions
Questions aboutsimilarity checks.
Free scans, source coverage, and what to do with a match.
Is the plagiarism checker free?
You can paste a passage and open the scan without an account, but the scan runs in GPTHumanizer’s plagiarism checker, and its full match report requires a paid GPTHumanizer plan. Plans and allowances are shown there.
How long can my text be?
Between 100 and 100,000 characters per scan. Split longer documents into sections and keep a note of which section produced which result.
Will this match my Turnitin similarity score?
Not necessarily. Different services search different sources and use different settings, so their percentages are not directly comparable.
What similarity percentage is acceptable?
There is no universal threshold. A low percentage with one unattributed paragraph can be a bigger problem than a higher one made of cited quotations.
Does no match mean my work is original?
No. It means the scan found no overlap in the sources it could search. Attribution is still your responsibility.
Is my text stored?
Text is processed to produce the scan and handled under the privacy terms of the service that runs it. See our Privacy Policy for how we treat submitted content.
Check your sources
Find the overlap before your reader does.
Scan the passage, open each match, and leave every borrowed idea properly attributed.
Check for Plagiarism