What is duplicate content?

Duplicate content refers to the same content that appears on multiple URLs, whether on your site or any other site.

Search engines classify each URL as a separate page, so having the same content on more than one URL is detected as duplicate content.

How does duplicate content affect SEO?

Duplicate content—both on your site and on external sites—affects your SEO in many ways.

Here are five of the biggest SEO drawbacks of duplicate content:

1. Dilution of Link Equity Across Different URLs Displaying Duplicate Content

When multiple pages on a website contain identical or substantially similar content, backlinks to these pages are spread out rather than concentrated. This means that each duplicate page only receives a fraction of the total link juice that could have been directed to a single, authoritative page.

As a result, the overall strength needed to boost search engine rankings is weakened. None of the duplicated pages may perform as well as they could have if all the link equity were focused on one primary source, leading to missed opportunities for higher visibility.

2. Exhaustion of Your Site’s Crawl Budget

Search engines allocate a certain amount of resources for crawling each site, known as the crawl budget. So, when you have duplicate content across multiple URLs, search engines need to spend more of these resources on crawling and processing these duplicates.

This increased usage means that important or new pages may be crawled less frequently or not at all, as the crawl budget is exhausted on redundant content. As a result, your site’s ability to have new and updated content indexed promptly is weakened, potentially reducing its visibility on the search engines.

3. Poor User Experience for Your Site Visitors

Duplicate content can create a confusing navigation experience for users. When visitors find similar content on multiple pages, it becomes frustrating and harder for them to locate the specific information they need.

This confusion diminishes the overall user experience, which search engines take into account when ranking sites. In addition, a poor user experience can lead to decreased time on your site and higher bounce rates, further harming your SEO performance.

4. Confusion for Search Engines When Crawling and Indexing Your Site

Search engines aim to show the most relevant content to users. When they find multiple versions of the same content, it becomes unclear which one to index and rank.

This confusion can lead search engines to choose a less optimal version or sometimes exclude all versions from search results. As a result, your content may not appear as intended, reducing your site’s visibility.

5. Missed Opportunity to Target Additional Search Terms

Lastly, duplicate content means you may not be taking advantage of opportunities to diversify your site’s content and target a wider range of search queries. By creating unique, quality content for each page, you can capture more search terms and address the specific needs of different audience segments.

Myth Debunked: There is no SEO Penalty for Duplicate Content

A common SEO myth is that Google penalizes sites that contain duplicate content. This is not true—according to Google’s Senior Webmaster Trends Analyst John Mueller.

Nevertheless, Google often filters out pages with duplicate content to prioritize and display the most relevant page on its SERPs. So, if you have duplicate content on multiple URLs or shared between your site and another domain, you may lose some valuable traffic given the drop in SERP exposure.

13 Common Duplicate Content Issues & How to Fix Them

There are many reasons why duplicate content may exist. Often, it is caused by technical issues or by accident, rather than someone intentionally cloning a page. Depending on the cause, there are different ways to fix duplicate content. Here are the 13 most common duplicate content issues and how to resolve each one.

1.   Homepage Canonicalization

Duplicate content caused by homepage canonicalization occurs when your homepage bears multiple URLs. In this case, users may be able to access your homepage via any of these sample URL variations:

• example.com
• www.example.com
• example.com/index.html
• www.example.com/index.html

So, if you do not set up redirects or signal your preferred subdomain to Google, it may index each URL as a different page, thereby diluting link equity across those various URLs.

What is the solution to duplicate content caused by homepage canonicalization?

Set up a 301 redirect to your preferred homepage URL. A 301 redirect signals to search engines that a page has moved permanently. Specifically, you’ll configure the server to redirect all traffic from the non-preferred versions of your homepage to the chosen URL. The method to set this up can vary depending on your web hosting environment:

• For Apache servers, edits might be made in the .htaccess file.
• For Nginx servers, changes would be made in the server block configuration.

2.   Content Syndication

Content syndication refers to the republishing of your web-based content by an external domain (i.e., third-party publications and channels).

Although content syndication can help you reach a broader audience, Google may identify republished content as duplicated if not done correctly.

And while sources with republished content are usually filtered out, there is still a chance of Google ranking the external site higher than the original, particularly if it has higher domain authority. This can result in a loss of valuable traffic for your site.

What is the solution to duplicate content caused by content syndication?

If a third-party publication wishes to republish your content, ensure that they clearly state the source, include a backlink to your original article, and ideally include a canonical link.

On the flipside, if you wish to replicate content from another site, consider creating original content unique to your brand that targets similar keywords instead.

3.   URL Capitalization

URLs are case-sensitive to search engines, meaning that the seemingly same URL with and without capital letters count as two different pages. Thus, URL capitalization inconsistencies across your site would constitute as duplicate content.

For example:

• https://www.example.com/page1.html
• https://www.example.com/Page1.html

What is the solution to duplicate content caused by inconsistencies in URL capitalization?

Choose one letter case and stick to it. Generally, using lowercase by default is the recommended best practice.

If you are fixing capitalization for existing pages, set up 301 redirects to the preferred, non-capitalized URL.

4.   Subdomains

For search engines, subdomains are considered separate sites, so content on your subdomains does not directly contribute to the traffic and rankings of your root domain.

Thus, having subdomains may also potentially lead to duplicate content that competes with content from your root domain. An encounter with duplicated content while navigating subdomains could look something like this:

• Step 1: User lands on the homepage of the root domain: www.example.com
• Step 2: From the homepage, the user clicks into the blog subdomain: blog.example.com
• Step 3: From the subdomain, the user then clicks on the About Us page: blog.example.com/aboutus.html. But this houses the same content as the root domain at www.example.com/aboutus.html.

What is the solution to duplicate content on subdomains?

Apart from implement 301 redirects to the preferred subdomain for that page, you can also use canonical tags to tell search engines the preferred page to index.

In the head section of the HTML of the subdomain versions of your page, insert a link element pointing to the URL of the preferred version: <link rel=”canonical” href=”https://www.maindomain.example/page” />. By correctly implementing canonical tags, you add a layer of specificity that guides search engines more clearly, thus helping you manage the duplicate content issue.

5.   HTTP vs HTTPS Duplication

Pages with different protocol headers—http:// and https://—are considered separate pages and so are pages with and without the “www” prefix. This means you could potentially end up with four URLs with the same content.

And if multiple versions of these URLs are crawlable and indexable to search engines, duplicate content issues may arise.

An un-optimized user navigation journey due to protocol-induced duplicate content could look like this:

• Step 1: User starts at the homepage: http://www.example.com
• Step 2: The user then clicks into a page that asks them to share personally identifiable financial information (PIFI) and therefore requires a secure encrypted connection (https://www.example.com/pifi.html).
• Step 3: The user then decides not to fill out the information and returns to the homepage, but this time at https://www.example.com, which has the same content as the unencrypted page bearing the seemingly same URL (http://www.example.com).

What is the solution to duplicate content caused by HTTP vs HTTPS duplication?

Standardize all your URLs.

Firstly, decide whether you want to use HTTP or HTTPS and whether you want to include the “www” prefix. Generally, search engines like Google prefer HTTPS for SEO best practices. If you are switching from HTTP to HTTPS, note that Google treats URL changes as site migrations.

And to make the change, you can set up 301 redirects to point all URL variations to your preferred domain.

6.   Trailing Slash

A trailing slash is the forward slash at the end of a URL. URLs with and without trailing slashes tend to be recognized as two different pages, for example:

• https://www.example.com
• https://www.example.com/

What is the solution to duplicate content caused by inconsistencies in the trailing slash?

You should outright avoid creating two versions of a URL—i.e., with and without trailing slash.

Stick to one version and stay consistent in your sitemap and internal linking, as search engines perceive URLs with and without trailing slashes as two distinct pages, potentially diluting the link equity passed through internal links if both are used. If you find two versions of a URL on your site already, set up a 301 redirect to your preferred version.

7.   URL Parameters

URL parameters are widely used to help filter products on a page, track sessions, attach affiliate codes, and more.

Most URL parameters are for tracking purposes and do not alter page content, but some do so to improve a page’s user experience—it is not necessary to have these crawled or indexed by search engines.

In addition, the particular ordering of your parameters is also crucial, especially when dealing with URL parameters that filter a page’s content. The following URLs, for instance, would be a duplicate of each other:

• www.example.com/book?color=red&cat=3
• www.example.com/book?cat=3&color=red.

What is the solution to duplicate content caused by inconsistencies in URL parameters?

Firstly, decide which parameters need to be indexed. This will vary depending on your business nature and may require keyword research to identify your most relevant parameters.

Then, set a canonical tag that references the page that should be indexed, which will ensure that search engines do not neglect the necessary parameters.

Alternatively, for Google and Bing, you can specify your parameters—and their intended purposes—in Google Search Console and Bing Webmaster Tools, respectively, essentially recommending which parameters to ignore and which to index.

8.   Websites Going Global

When a company expands globally or creates localized content for overseas markets, duplication may arise if they re-use content from their root domain (www.example.com) across the different region-based ones (www.example.co.uk).

What is the solution to duplicate content caused by websites going global?

Regardless of language, SEO best practice dictates that content should always be unique and localized—not just translated—for your target market. If not, then there’s simply no point in creating a separate regional site, and you would be better off dedicating your resources to expand the global reach of your root domain.

So, when creating localized versions of your website, remember to set up hreflangs as well as language and location targeting to drive higher conversions.

You can learn more about this in our guide on the best practices for international SEO.

9.   Tag and Category Pages

Many blog sites have both tags and category pages, which simplifies content discovery and makes for a more enjoyable user experience.

Search engines, however, may recognize some of these pages as duplicates, especially for categories and tags that are too similar.

What is the solution to duplicate content caused by tag and category pages?

Use the meta robots tag “noindex” in the head section of the HTML to instruct Google not to index certain category and tag pages, particularly those with too little on-page content to describe it accurately to crawlers.

10.   Print Versions

Generally found on online news publications, print versions are reproductions of a webpage’s content—minus the images and styling elements.

Often, however, clicking on the print button would lead you to a separate URL (e.g., www.example.com/news-today/print) with the print version of the page. Subsequently, search engines may confuse between the print and original versions and consider them duplicated on two separate pages.

What is the solution to duplicate content caused by print versions?

Whether you have set up a different URL or parameters for the print version of your page, you should also set up self-referencing canonicals that point to its original version.

11.   Different Desktop & Mobile URLs

Some sites may have mobile and desktop versions that share similar content but have different URLs, such as:

• www.example.com/m.html (desktop version)
• www.example.com.html (mobile version)

This, too, can confuse search engines and lead to duplicate content issues.

What is the solution to duplicate content caused when URLs differ for desktop and mobile?

Ideally, sites should have the same URLs across all devices. In other words, there is no need to create a separate mobile site—you should instead adopt a responsive site design that can identify the user’s device and adjust the style elements accordingly.

12.   Pagination

Pagination occurs when you separate your content—especially long-form blogs, news articles, or product listings—into multiple discrete pages to break it up. And although each page may contain different content, Google may still detect them as duplicates since they all focus on the same topic with very similar wording.

What is the solution to duplicate content caused by pagination?

There are several solutions to fix pagination issues.

One option is optimizing the root page you want to rank for on the SERP while de-optimizing the other consecutive pages. You can do this by updating the H1 tags and adding relevant and quality content—including images with optimized alt text—unique to the root page.

You can also enter the URL parameters for pagination into Google Search Console to help Google understand what they are for and what to do with them.

Thirdly, you can implement the “next” and “prev” tags in the HTML to indicate pagination relationships between the pages. This coding will prevent the paginated pages from being seen as duplicates by search engines.

Lastly, if you are absolutely sure that there is no purpose for the paginated pages to appear on the SERP, use the meta robot tags “noindex” in the head section of the HTML to prevent them from being in the index.

13.   Similar Product Names

Duplicate issues may arise when different products share similar product names, which regularly transpires in online marketplaces where users buy, sell, and list products.

Let’s assume that two sellers are listing two different items but name them too plainly (like “white sneakers”) such that they duplicate each other. So, when their product listings go live, their URLs and title tags become too alike:

• https://www.example.com/listing/123/white-sneakers
• https://www.example.com/listing/456/white-sneakers

Therefore, if a product page has too similar product naming conventions as other related product listings, search engines will likely identify them as duplicates.

What is the solution to duplicate content caused by similar product names?

Add a unique identifier in the title tag. For instance, you can attach a unique product number to each listing or use a seller name or ID. Additionally, you can mandate that other sellers change their product name if it already exists in the database.

Ultimately, each product has its unique selling points, so differentiate your listing by highlighting these to stand out among competitors.

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And there you have it! With solutions to the 13 most common duplicate content issues, as well as an understanding of their causes, you should be well-equipped to improve your site rankings and optimize your UX against duplicate content.

Remember that the best way to avoid duplicate content altogether is by creating unique content and maintaining a clear site structure that both users and search engines can easily understand.

This article has been updated by Helena Xiao in 2024.