Arclab® Website Analyzer


Search Your Website for Duplicate HTML Content
Find All Duplicate Pages without a Canonical Link Tag



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What means "Duplicate HTML Content"?

In this context, "Duplicate HTML Content" means that exactly the same HTML page can be accessed under 2 different URIs. For this purpose, a checksum is created for each HTML page and all pages found during the scan are compared with each other.


Excepted from the report are:

How can I Find "Duplicate HTML Content" on My Website?

Troubleshooting is easy with Arclab® Website Analyzer. First, let the program scan your website.
After the scan of your website is completed, you will receive a detailed report containing all errors found on your website and other information:


Website Analyzer Report


In the "Duplicate HTML Content" line, click "Show Details" to display details about the errors:


Details: Duplicate HTML Content


  • At least 2 HTML pages listed under (A) contain exactly the same content or have the same checksum (B).
  • This error can occur, for example, if you have renamed pages but the old page is still on the server and there are still links to the old page.
  • However, if this is intentional or for technical reasons, you should insert a "rel=canonical" link tag in the HTML header to avoid negative effects on the search results.

"rel=Canonical" HTML Header Link Tag

The "rel=canonical" link tag in the HTML header is used to prevent duplicate content issues in search engine optimization (SEO) by indicating the "canonical" or "preferred" version of a web page.



<!doctype html>
<html lang="en">
<link rel="canonical" href="https://www.yourdomain.tld/some-page.html">




Insert the same (!) "rel=canonical" link tag in both pages and specify which URI should be used.