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Plagiarism Checker
Paste a passage and see what share of it appears in published sources, which sources those are, and the exact wording that matched.
Plagiarism checker
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A match is not automatically a problem
A quotation you introduced and cited should match its source exactly — that is what a quotation is. So should a technical definition, a statute, or a standard formula. A checker cannot tell the difference between correct quoting and copying, which is why the result lists the sources instead of just showing you a percentage.
The question to ask of each match is not whether it overlaps but whether it is attributed. Where the answer is yes, the match is doing its job.
Where the real risk sits
The passages that cause trouble are usually the ones that do not match at all: an idea taken from a source and reworded far enough to slip past a checker, with no citation attached. That is still plagiarism, and no percentage will catch it. Only you know where your ideas came from.
The second common failure is the patchwork paraphrase — a sentence rebuilt from the original with a few synonyms swapped in. It often matches partially, and it is treated as plagiarism even where a citation is present, because the wording was never yours.
Reading the source list
Each result shows the share of your text that source accounts for and the exact sequences that matched. Where a source was already cited in your text, it is marked, so the list separates into matches you have accounted for and matches you have not.
Content aggregators and quote sites turn up often. A match against one of those usually means both you and the aggregator are quoting the same original — track down what that original is, and cite that.
What to do with a high percentage
Work through the sources one at a time. For each, decide whether the passage should be a quotation with a citation, a paraphrase written properly in your own words with a citation, or cut because it is not carrying its weight.
If most of the piece is other people's material, the fix is not editing the wording. It is deciding what your own argument is, and rebuilding around it.
Related tools and guides
- AI detector The other question markers ask
- Citation generator For the sources you need to attribute
- Annotated bibliographies Summarising sources properly
- Editing and proofreading A human read before submission
Frequently asked questions
Is this plagiarism checker free?
Yes, up to 1,000 words per check with no account. Check the sections you are least sure about rather than pasting a whole dissertation.
Does it check against Turnitin's database?
No. Nothing outside an institution can, because that database is built from student submissions and is not open to anyone else. This searches published web sources, which is a different corpus.
What is an acceptable similarity percentage?
There is no universal figure, and any site quoting one is guessing. A paper full of properly cited quotations can score high and be entirely sound. Read the matched sources rather than the number.
Will my paper be added to a database?
No. The passage is checked and not retained, so submitting it here will not cause your own work to be flagged against you later.
Does citing a source stop it being plagiarism?
For a quotation, yes, provided it is marked as a quotation. For a paraphrase, the citation is necessary but not sufficient — the wording also has to be genuinely yours rather than the original with substitutions.
Why does it match sites I have never read?
Usually because both you and that site are drawing on the same original source, or because the site has copied the material you are quoting. Trace the passage back to where it first appeared and cite that.