Text Similarity Checker
Compare two texts and see how much they overlap, with the shared passages listed.
About this tool
Compares two texts and reports how much they have in common, listing the passages that appear in both.
It matches on runs of five words rather than character similarity, because that is what "these two pages say the same thing" actually means. Two descriptions of the same product share phrases; character-level similarity would call any two English texts moderately alike.
This is not a plagiarism checker. It compares the two texts you paste and has no index of the web to check against, so a low score here says nothing about whether your text appears elsewhere.
Common questions
Is this a plagiarism checker?
No. It compares two texts you supply. A plagiarism checker compares against an index of the web, which needs a crawl this tool does not have. A low score here means the two texts differ, nothing more.
What counts as too similar?
There is no threshold, and anyone quoting one is inventing it. What matters is whether the pages serve a different purpose. Two product variants sharing 70% of their description is normal; two landing pages sharing 70% probably should be one page.
Does duplicate content get penalised?
There is no penalty for it in the ordinary case. Search engines pick one version and ignore the rest, so the cost is that the wrong one may be chosen, and your effort is split. Deliberate scraping is treated differently.
Why five-word runs?
Short enough to catch a rewritten sentence that kept its structure, long enough that ordinary English phrasing does not match by coincidence. Three-word runs match everything; ten-word runs match only verbatim copying.