Plagiarism Checker
Basic similarity check.
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How text similarity is measured
Comparing two texts for overlap is a well-defined problem. Shingling breaks each document into overlapping runs of words, then measures how many runs the two share — the Jaccard similarity. Fingerprinting hashes those runs so large texts can be compared quickly. Both detect copied passages even when a few words have been changed, because the surrounding runs still match.
What this cannot do is search the internet. A true plagiarism service compares your text against a crawled index of billions of pages and an archive of previously submitted student work; that index is the entire product, and it exists on their servers. A browser-based tool compares the documents you give it against each other. That is genuinely useful for a specific and common task — checking two documents you both hold — and it is honest to say it is not the same thing as a web-wide check.
Why we built this tool
Teachers compare two submissions that read suspiciously alike. Editors check a draft against a source it was based on. Writers verify that a rewritten passage is sufficiently different from the original. Content teams check a new article against an old one to avoid duplicating themselves.
Student work and unpublished drafts are sensitive, and commercial plagiarism services routinely retain everything submitted to them, adding it to the very database they check future submissions against — which is a poor outcome for an author's own unpublished manuscript. Ours compares in your browser and keeps nothing. Nothing is uploaded, nothing is indexed, and no copy of your text exists anywhere after you close the tab.
Tips and common mistakes
- This compares the two documents you provide; it does not search the web.
- Read the matched passages rather than reacting to the percentage alone.
- Quoted and cited material legitimately matches its source and will show as overlap.
- Boilerplate such as legal disclaimers matches across unrelated documents and means nothing.
Open Plagiarism Checker with a link
Plagiarism Checker can be handed its input by the link that opens it, so the page arrives with the work already done. This is meant for assistants and scripts: if a chatbot, an editor extension, or a command-line agent already holds your content, it can build a link instead of asking you to copy and paste into a box.
The payload rides in the fragment — the part of a URL after the #. Browsers never send the fragment to a server, so anything handed over this way stays on your device exactly as a dropped file would. A link that uses the query string instead is rewritten into the fragment by the page before any analytics or ad script can read the address.
Prefix any field with gz — #gztext= — to pass it as gzip-compressed base64url, which fits roughly five to ten times more into the same link. Links stay reliable up to about 8,000 characters; past that, chat apps and address bars start truncating them, and the page says so rather than loading half a document.
One exception to the privacy rule: ?url= tells the page to download the input from an address. That request goes from your browser straight to that server — not through ours — but it does leave your device, and it only works if the server allows cross-origin requests.
#text=— the text to work on
Example: https://mygadgets.ink/tools/plagiarism-checker/#text=...
Quick start: using Plagiarism Checker
- Paste the first document into the input above.
- Paste the document you want to compare it against.
- Run the comparison to see the similarity score and the matching passages.
- Read the matched sections rather than trusting the percentage alone.
- Remember this compares the two texts you supplied, not the whole web.
For a straight line-by-line view of the differences, Diff Checker is clearer.