Duplicate Content: Why It Happens and How to Fix It

Want to know what duplicate content is and how it affects SEO? Duplicate content can worry many website owners.

We often read that having the same content in different places can harm our website. Some even say it could lead to a Google penalty.

Thankfully, that’s not exactly true. But still, duplicate content can cause SEO problems. Since around 25–30% of the web is duplicate content, it’s important to understand it and learn how to fix it.

What is duplicate content?

Duplicate content means the same or very similar text that appears in more than one place on the internet. It can be found on just one website or across many websites.

Why is duplicate content bad for SEO?

Google says there’s no direct penalty for duplicate content. But it can still hurt our SEO in a few ways, like:

• Showing bad or confusing URLs in search results
• Splitting the value of backlinks
• Wasting crawl budget
• Other websites copying our content and ranking higher

1. Bad or confusing URLs in search results:

Let’s say the same page appears at three different web addresses:

• domain.com/page/
• domain.com/page/?utm_content=buffer&utm_medium=social
• domain.com/category/page/

We want the first one to show in search results. But sometimes Google picks the wrong one. If an ugly or confusing URL shows instead, fewer people may click on it. This means we could get less traffic from search engines.

2. Backlink dilution:

If the same content appears at different URLs, people might link to all of them. That spreads the link value between those pages, which isn’t good for SEO.

For example, there are two pages that are nearly the same. One has 106 backlinks, and the other has 144. That’s a lot of links going to two separate pages.

Now, don’t worry too much—Google tries to fix this.

When it sees similar content, it groups the URLs together and picks one to show in search results. Then it combines the value of all links for that group into one main URL. This is called canonicalization.

So in this case, Google should choose one of the URLs and count all the backlinks for it (106 + 144).

But that’s not always what happens. Sometimes, Google shows both pages in search results for similar keywords. That can still create confusion.

3. Uses Up Crawl Budget:

Google finds new content on our website by crawling, which means it follows links from one page to another. It also comes back from time to time to check if anything has changed.

When we have duplicate content, it makes Google do more work. This can slow down how often and how quickly they check our new or updated pages.

That’s not good because it might delay when new pages show up in Google, or when updates to old pages are noticed.

Note: Google crawls faster on websites that are quicker and more responsive. So this problem is more common on slow websites with limited hosting power. Google also tends to visit duplicate pages less often.

4. Other Websites Ranking Higher with Our Content:

Sometimes, we allow another site to republish our content. This is called syndication. But other times, some websites copy our content without permission. That’s called scraping.

In both cases, the same content appears on many websites. This usually doesn’t cause big problems.

But if the copied version shows up higher in search results than our original one, then it becomes a real issue.

The good news is this doesn’t happen very often, but it can.

Does Google Give a Duplicate Content Penalty?

Google has said many times that there’s no direct penalty for duplicate content.

But this isn’t fully true. If we copy content by mistake and not to cheat the system, then we won’t be punished. But if it’s done on purpose to trick search engines, we might get penalized.

Now the question is: what does “trying to cheat rankings” really mean?

Google explains this in detail, but here are a few examples:

• Making many pages or websites with the same content just to show up more in search
• Copying other websites’ content without adding anything new
• Using affiliate product descriptions (like from Amazon) without improving or changing them

So, even if there’s no direct penalty, having duplicate content can still harm our SEO.

Common Causes of Duplicate Content

There isn’t just one reason why duplicate content happens. There are many.

Filtered Pages (Faceted Navigation)

Filtered or sorted pages are common on online shopping websites.

These filters add extra text to the end of the web address (URL).

Because there are so many filter choices, the same content can show up in many different versions.

Tracking Links

Some websites add special codes (called parameters) to URLs to track where visitors come from.

For example, we might add this to check clicks from our email newsletter:

example.com/page?utm_source=newsletter

This creates another version of the same page.

Session IDs

Some websites use session IDs to remember visitor actions.

These also add long strings to the URL, like:

example.com?sessionId=abc123xyz

This can also create duplicate pages.

HTTPS vs. HTTP and www vs. non-www

Websites can be opened in different ways:

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

If we don’t set up our site the right way, it may open in more than one version. That can lead to duplicate content.

Capital Letters in URLs

Google sees URLs with capital and small letters as different.

So these are all different to Google:

• example.com/page
• example.com/PAGE
• example.com/pAgE

Trailing Slash or No Slash

Google treats these as different pages:

• example.com/page/
• example.com/page

If both versions work, it can cause duplicate content. It’s better if one redirects to the other.

Print-Friendly Pages

Some websites create special pages for printing. The content is the same, but the URL is different:

• example.com/page
• example.com/print/page

This is also seen as duplicate content.

Mobile Pages

Mobile versions can also have different URLs, even though the content is the same:

• example.com/page
• m.example.com/page

AMP Pages

AMP (Accelerated Mobile Pages) a faster-loading version of pages, but they are often copies:

• example.com/page
• example.com/amp/page

Tag and Category Pages

When we tag posts, many CMS platforms make new pages for each tag.

For example, one article might be listed on both “protein powder” and “whey” tag pages. If those are the only articles with those tags, then the pages look the same.

That causes duplicate content.

Image Attachment Pages

Some CMS platforms create separate pages just for images. These pages often have only the image and some default text.

Since that text is reused, it leads to many pages with the same content.

Comment Pages

Websites like WordPress can break comments into different pages:

• example.com/post/
• example.com/post/comment-page-2
• example.com/post/comment-page-3

These comment pages repeat the post and create similar content across URLs.

Language or Region Versions (Localization)

If we show the same content to users in different countries who speak the same language, like the US, UK, or Australia, the pages can be nearly the same.

There might be small changes like price or spelling, but the rest of the page is still a copy.

Search Results Pages

When people search on our website, they’re often taken to a new page with a unique URL, like:

example.com?q=search-term

These pages are another source of duplicate content.

Staging Environments

A staging site is a copy of our real website used for testing.

We might use it to try a new plugin or make design changes safely.

But if Google finds and indexes this test site, it becomes a duplicate of our main site and can hurt SEO.

How to Check for Duplicate Content Issues Across the Web

Sometimes, other websites copy our content. This is called content scraping.

If these copied pages show up in Google above our original page, it can become a problem.

This usually happens to new or smaller websites. That’s because the websites copying the content might have more trust or authority in Google’s eyes. Google might think their version is the original one.

If our site is small, we can search a few lines of our text inside quotes on Google. This can help us find pages that copied our content.

Most of the time, these will be low-quality or spammy websites.

In general, we don’t need to worry about those. But if a real, trustworthy website copied our content and seems to be taking our traffic, we can check it using a tool.

If their version is getting more visitors than ours, we may need to take action.

Here are three things we can do:

• Ask the website to remove our content.
• Ask them to add a canonical link pointing to our original page.
• Report it to Google using a DMCA takedown form.

If we are sharing our content on other websites on purpose, we should ask those sites to add a canonical link. That way, Google knows which version is the original.

Final Thoughts

We shouldn’t worry too much about duplicate content. It’s often not a big problem.

If we only have a few duplicate pages or use small parts of content from other sites, it’s usually okay. Google knows how to handle this kind of thing.

But we should watch out for technical problems that make many duplicate pages by mistake. For example, badly set up filters on online shopping websites can create hundreds of similar pages.

That can waste our crawl budget and hurt our SEO in the long run.