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Uppercase & Lowercase Duplication

Uppercase & Lowercase Duplication


Duplicate Content & Canonicalisation – Uppercase & Lowercase URLs

URLs are often created using more semantic language as if the user is writing a sentence; consequently, this can result in all sorts of bad practices creeping in.

One of these very common mistakes is using uppercase characters in the URLs of your website, because some hosting servers are case sensitive, treating these as completely unique pages. It is because of this that canonical duplication problems can occur when a site uses uppercase characters.

This article is one of several that fall under the duplicate content and canonicalisation series in the Raptor Knowledge Base. Please the below list for all other articles covering all of the different types of duplicate content and canonicalisation issues that a website can experience below:

Uppercase & Lowercase URLs

The URL to any webpage should be created in lowercase characters and should include no uppercase characters. For example: - Correct - Wrong

On Apache servers URL’s are case sensitive and can be seen as unique pages.

When creating webpages depending on your method to do so it may be that the CMS automatically generates a URL based on the main heading or page title. This can lead to URL’s containing uppercase characters being created.

Similarly it may be that a webpage is linked to either internally or externally (from another website) using uppercase characters.

Often users type a URL into their web browser, of the webpage that they want to access, naturally people write with grammar and hence a URL may be entered that contains uppercase characters.

Impact of Issue

When a web page is accessible from more than one URL the possibility for Google to view all bar one of those pages as duplicate content. Google and other search engines can devalue duplicate content, which can result in a loss of rankings and consequently traffic, for terms targeted on those pages.

Hence if a site is accessible from both uppercase and lowercase variants of the same URL, this could have a negative impact on your website’s content.
On Windows servers this is not an issue because URL’s are case insensitive but on Apache / Linux servers this is an issue.

How to Resolve

There are a number of steps that can be taken to ensure that this does not become an issue on your site. The first forces lowercase URLs to be used and the second is a catchall solution for duplicate content.

There is no ‘SEO’ reason to force URL’s to lowercase; it just makes more intuitive sense to do it this way. Should you choose to do so, the issue could be resolved by forcing all characters to uppercase.

Raptor Tools!

Use Raptor’s SEO tools to analyse your site to determine if there are any uppercase & lowercase duplication issues. Our SEO auditing and web crawler software can easily and quickly identify uppercase & lowercase duplication issues.


You will need ‘write / modify’ access to the website’s .htaccess file in order to implement this solution. We always warn people that modifying the .htaccess file can have drastic effects on website functionality if implemented incorrectly. Always test immediately after publishing changes to the file.

Copy the code below into the .htaccess file, save and upload it to the root of the domain overwriting the existing file.

RewriteEngine on
RewriteBase /

# force url to lowercase if upper case is found
RewriteCond %{REQUEST_URI} [A-Z]
# ensure it is not a file on the drive first
RewriteCond %{REQUEST_FILENAME} !-s
RewriteRule (.*) rewrite-strtolower.php?rewrite-strtolower-url=$1 [QSA,L]

Canonical Tags

This is a topic mentioned in greater detail in another article specific to canonical tags but for the purpose of this article; adding a canonical tag to every page of the site (following the guide above) will prevent most duplicate content issues on any site.

Benefit of Resolving

Controlling the URL’s from which your site & pages can be accessed prevents the potential impact from duplicate content issues.


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