Compare two texts you paste in. This reports word overlap only — it does not search the web or detect plagiarism against published sources.
What This Tool Does and Does Not Do
This is a text similarity checker. You paste a reference text into the first box and your own text into the second, and it reports how much of their vocabulary is shared. It is honest to call it a similarity checker rather than a plagiarism checker.
It does not search the internet, it does not query any database of published work, and it has no index of academic papers or web pages. If you paste a single text and expect it to find where the words came from, it cannot do that. It only ever compares the two texts you supply.
How the Score is Calculated
Both texts are lowercased, stripped of punctuation and split into words. The tool then builds the set of unique words in each, counts how many appear in both, and divides that by the total number of distinct words across the pair.
The result is a percentage of shared vocabulary. It is a real calculation, not a random number, but it measures word overlap rather than copying.
How to Read the Percentage
Because common words such as "the", "and" and "of" appear in almost all English text, two entirely unrelated passages on a similar subject will still score noticeably above zero. A moderate score is therefore not evidence of anything.
A high score means the two texts draw on much the same vocabulary, which is worth investigating. It is a prompt to read both passages yourself, not a verdict. Equally, reworded copying can score low while still being plagiarism, because the words changed even though the substance did not.
What It Is Genuinely Useful For
- Comparing your draft against a source you were working from, to check how closely you followed it.
- Checking two documents for substantial duplication.
- Comparing two versions of your own writing.
- Spotting heavy repetition between sections of a long document.
If You Need Real Plagiarism Detection
Proper plagiarism detection requires comparing your work against a large index of published and submitted material, which is what institutional services are built to do. If you are submitting academic work, use the service your institution provides.
Word order is also ignored here. Two texts with identical vocabulary in a completely different order score the same as two identical texts, which is another reason not to read this figure as an originality result.
Privacy and Processing
Both texts stay in your browser and the comparison is calculated locally. Nothing is uploaded, stored or logged.
Text Similarity Checker FAQ
Does this search the internet for plagiarism?
No. It only compares the two texts you paste in. It has no index of web pages or academic papers, so it cannot find where a piece of text came from.
How is the similarity percentage calculated?
Both texts are lowercased, stripped of punctuation and split into words. The tool counts the unique words appearing in both, then divides that by the total number of distinct words across the pair. It measures shared vocabulary, not copying.
What is a normal similarity score?
Because common words such as the, and and of appear in nearly all English text, two unrelated passages on a similar subject will still score noticeably above zero. A moderate score is not evidence of anything on its own.
Can a low score still mean plagiarism?
Yes. Reworded copying can score low while remaining plagiarism, because the words changed even though the substance did not. Word order is also ignored, so the figure should never be read as an originality verdict.
What should I use for real plagiarism detection?
Proper detection requires comparison against a large index of published and submitted work. If you are submitting academic work, use the service your institution provides.
Is my text uploaded?
No. Both texts stay in your browser and the comparison is calculated locally, so nothing is uploaded, stored or logged.
Related Developer Tools
Keep moving through common developer workflows with Text Compare, Word & Character Counter, Synonym Rewriter. You can also browse the full Developer Tools collection or return to the all tools hub.