Duplicate Content Detector

The Duplicate Content Detector compares two pieces of content side-by-side and calculates a similarity percentage, highlights matching sentences, and provides an SEO risk assessment for potential duplicate content issues. Duplicate content is one of the most misunderstood problems in SEO: while Google does not impose a formal 'penalty' for duplicates, it does choose only one version to index and rank, which means the other versions are effectively invisible in search results. This filtering can devastate your traffic if Google picks the wrong version or if a competitor has scraped your content and their version outranks yours. The similarity percentage gives you a clear threshold to work with — content with more than 25% sentence-level similarity should be reworked, and anything above 50% is a serious risk that requires immediate attention. The side-by-side diff view highlights exactly which sentences match, making it easy to identify whether the overlap is in boilerplate sections like disclaimers and CTAs (which are lower risk) or in the substantive body content (which is higher risk). Use this tool in several common scenarios: checking whether your own pages are too similar to each other, verifying that content you have commissioned from freelancers is original, and monitoring whether competitors are copying your published work without attribution. When the risk rating comes back as high, rewrite the overlapping sections using different examples, angles, and sentence structures rather than just swapping individual words, because Google's algorithms are sophisticated enough to detect shallow paraphrasing. Pro tip: run this comparison between your draft and the top three ranking pages for your target keyword before publishing, because if your content is too similar to what already ranks, Google has little reason to surface a near-duplicate when the existing results already satisfy the query.