Content that is found on more than one website or more specifically webpages is known as Duplicate Content. The content may be completely similar or partially similar. Search Engines penalize websites having similar content.However some websites may have similar pages on them unknowingly.An example of this would be an eCommerce site selling items and providing search results based on price or color. The search results would display the similar products but would two different urls having the same content. Hence, to solve this issue of duplicate content within the same domain, you can use canonicalization. But, in other cases, such as copying content from other websites, the search engines tends to penalize sites and may remove the duplicate pages from their search results.
Duplicate Content Checkers
There are several content checkers available on the internet, you can use to check duplicate content. Some of the best ones are given below:-