Duplicate Content Checker

What counts as duplicate content

Duplicate content is substantial blocks of text that are identical or very similar across more than one URL, on your own site or across different sites. Most of it is not deliberate. Common causes include:

• The same product description on several colour or size variants.
• Location pages that only swap the city name.
• URL parameters, print versions, http and https or www and non-www versions of a page.
• Tag, category and archive pages that repeat the same post excerpts.
• Manufacturer descriptions or press releases used by many other sites.

Google does not hand out a penalty for ordinary duplication. Instead it groups similar pages and shows only one of them, which may not be the one you want, and splits signals such as links between the copies. Large amounts of thin, near-identical pages can also make a whole site look low value.

How the similarity score is calculated

The duplicate content checker uses shingling, the same family of technique search engines use for near-duplicate detection. Each text is broken into overlapping sequences of words (by default 4 words long). The score is the share of sequences the two texts have in common, out of all the distinct sequences in either text, known as the Jaccard similarity.

Change Match sensitivity to suit the job. Shorter sequences (3 words) also catch lightly reworded text. Longer ones (6 to 8 words) only count passages that were copied word for word, which is useful for spotting plagiarism of a specific paragraph. Below the scores, every identical sentence the two documents share is listed, and for two documents the matching passages are highlighted in place.

Checking your own site for duplicate content

The site duplicate content check is where this tool is most useful. Paste up to 10 URLs that you suspect overlap, such as product variants, city landing pages or two blog posts on the same topic, and the matrix shows every pair at once. Compare main content only ignores navigation, header, footer and sidebars, so shared site chrome does not inflate the scores.

Once you know which pages overlap, fix them:

• Merge pages that target the same search intent and 301-redirect the weaker one.
• Rewrite pages that need to exist separately so each has unique, useful content.
• Canonicalize true duplicates such as parameter URLs to the preferred version. Check the result with the canonical tag checker.
• Noindex thin archive and filter pages that add no search value.

Check a draft or guest post before publishing

Use Page vs your text to compare a draft against a live page: a writer's article against the source they were briefed on, a guest post against the author's previous post, or a supplier's product copy against your own listing. The highlighted passages show exactly which wording is shared.

This tool compares the documents you give it. It does not search the whole web for copies, which needs a web-scale index. For line-by-line edits between two versions, use text compare. To see which keywords each page leans on, use the keyword density checker.

What scores to expect

Even well-written, unique pages on the same site share some text: navigation labels, calls to action, legal notes and product specifications. With main content only, most unique pages score under 15% against each other. Product pages that share a long manufacturer description often land between 40% and 70%. Two near-identical location pages usually score above 80%. Use the matrix to rank pairs and work through them from the top.

Duplicate Content Checker: frequently asked questions