How to use the Text Similarity Checker
- Paste the first text.
- Paste the second text.
- Read the overall similarity percentage.
- Review the shared words and the word-by-word differences.
Example
| Input | “The cat sat on the mat” vs “A cat sat on a mat” |
|---|---|
| Result | ≈ 70–80% similar |
The three measures
Paste two texts and click Check similarity. The tool calculates three scores and shows their average as an overall percentage:
- Cosine similarity (word frequency): compares how often each word is used in both texts. It rewards texts that use the same words in similar amounts.
- Jaccard similarity (unique words): the share of different words that appear in both texts. It ignores how many times a word repeats.
- Character similarity (edit distance): how many letter changes it would take to turn one text into the other. It is calculated only when both texts are up to 4,000 characters.
Reading the result
- Below 20%: Different.
- 20% to 49%: Slightly similar.
- 50% to 79%: Somewhat similar.
- 80% and above: Very similar.
Under the scores you will find the list of words the two texts share, and a word-by-word comparison that marks inserted and deleted words. Tick “Ignore common words” to leave out words like “the”, “and” and “of”, so that the score reflects the meaningful words.
What it is good for
- Checking how much a rewrite differs from the original.
- Comparing two product descriptions, ads or pages to avoid near-duplicate content.
- Spotting whether two answers, drafts or summaries say nearly the same thing.
- Measuring how far a paraphrase moved from its source.
What it is not
This tool compares only the two texts you paste. It does not search the web or a database, so it is not a plagiarism checker, and a low score does not prove that a text is original. Word-based scores also cannot tell when two sentences mean the same thing in different words. For a detailed view of edits, use the Word Difference Checker or the Text Compare, and to reword text, try the Paraphrasing Tool.
Frequently asked questions
How is similarity calculated?
We combine three measures: cosine similarity of word frequencies, Jaccard overlap of unique words, and character-level edit distance for shorter texts.
Is this a plagiarism checker?
No. It compares only the two texts you paste. It does not search the web or other documents.
Why is the overall score an average?
Each measure has strengths and weaknesses, so averaging them gives a steadier overall result. You can read every score separately in the table.
Why is there no character similarity score?
It is calculated only when both texts are 4,000 characters or shorter. The other two measures still work on long texts.