Google's definition of duplicate content:

"Duplicate content generally refers to substantive blocks of content within or across domains that either completely match other content or are appreciably similar. Mostly, this is not deceptive in origin. Examples of non-malicious duplicate content could include:

• Discussion forums that can generate both regular and stripped-down pages targeted at mobile devices
• Store items shown or linked via multiple distinct URLs
• Printer-only versions of web pages

Google tries hard to index and show pages with distinct information. This filtering means, for instance, that if your site has a 'regular' and 'printer' version of each article, and neither of these is blocked with a noindex meta tag, we'll choose one of them to list."

If the content of a page can be found on multiple pages, Google only displays one of these pages in the search results. Unfortunately, this might not be the page that you want to see.

If your website contains duplicate content, the wrong pages might appear in Google's search results. For that reason, you should check your pages for duplicate content.

The easiest way to find duplicate content on your web pages is to use the Website Audit tool in SEOprofiler. The Website Audit tool checks all pages of your website and it informs you about errors that can lead to ranking problems.

Of course, duplicate content issues are among the things that the Website Audit tool finds. In addition to duplicate content, the Website Audit tool checks your web pages for many more things that can have a negative influence on your Google rankings.

There are several things that you can do to fix duplicate content issues. Of course, you can do nothing and hope that Google gets it right. Usually, this is not recommended. Better do the following:

• Use the rel=canonical tag to inform Google about the preferred version of a page. Details about the attribute can be found here. For most duplicate content issues, this is the best solution.
  
  
• Redirect the duplicate URLs with a 301 redirect to the original page. In that case, the alternate pages won't be displayed at all. This doesn't work with print pages, etc. because you want to display these pages.