Compare two Markdown docs for content overlap. Jaccard similarity, shared words, and shared phrases.
Free Markdown Content Similarity Checker compares two Markdown documents for content overlap using Jaccard similarity on unique word sets. It reports a similarity percentage, shared and unique word counts, and a list of shared two-word phrases. Markdown syntax is stripped so only prose is compared.
Privacy: This tool runs entirely in your browser. Your text is never uploaded, logged, or cached. Close the tab and it's gone. Verify in DevTools → Network: zero requests fire.
Comparing documents for overlap should not require a paid plagiarism checker. The comparison runs entirely in your browser.
| Input | Output | Typical size | Speed | Login needed |
|---|---|---|---|---|
| Two Markdown documents | Similarity %, shared words, shared phrases | Any document size | < 50 ms | No |
Here's what this free tool does in detail — every feature is built to solve real problems, runs entirely in your browser, and is free forever.
The tool calculates Jaccard similarity: the number of shared unique words divided by the total unique words across both documents. This gives a percentage that is independent of document length and focuses on vocabulary overlap.
Beyond single words, the tool finds two-word phrases (bigrams) that appear in both documents. Shared phrases indicate structural or topical overlap that single-word matching would miss.
For line-level comparison, use the Markdown Diff Tool.
See exactly how many unique words are in each document, how many are shared, and how many appear only in Document A or B. This breakdown helps you understand the nature of the overlap -- shared vocabulary vs. unique content.
Markdown formatting, code blocks, and inline code are stripped before comparison. Only prose content is analyzed, so formatting differences do not affect the similarity score.
For word-level analytics on a single document, try the Word Counter.
Paste the first Markdown document into the left pane.
Paste the second Markdown document into the right pane.
The similarity percentage, word counts, and shared phrases appear below the inputs.
Compare two articles to find duplicated content before publishing.
Check two papers for vocabulary overlap as a first-pass similarity check.
Find pages with high overlap that should be merged or differentiated.
Check how much a draft overlaps with reference material.
Identify docs that cover the same ground and should be consolidated.
Yes. Free forever, no account required.
Jaccard similarity: shared unique words divided by total unique words across both documents.
It measures overlap between two documents you provide. It does not check against external sources.
Two-word sequences (bigrams) that appear in both documents.
Yes. Formatting is stripped before comparison.
No. Both documents stay in your browser.