How to Optimize PDF Files for SEO
PDF files were first indexed by Google in 2001. The format is most often used for publishing technical and legal documentation, e-books, and various training material. Viewing content is available from almost any device and is displayed the same way on different screens, making it convenient to view and download.
Despite an official statement from Google, for a long time, people believed that the search engine does not index PDF files. Many optimizers claimed that pages that contained this format were not in the top 10. The reason for this was that the search engine could not decipher the content of the documents, which was different from the standard HTML code.
The myth was shattered in 2011 when Google officially announced that robots had indexed hundreds of PDF files since 2001.
Content in the PDF format has its tag that looks like this in the results:
The main barrier of getting into the top 10 is optimizing PDF files correctly. It is why the format is not particularly popular in SEO, which we will discuss later in the article.
PDF Files and SEO: is it rational to use them?
Let’s look at the main advantages and disadvantages of PDF files for search engine optimization.
The Advantages of Using PDF Files
1. Easily create content. PDF files are easy to create- just save the document from Word, Illustrator, or another tool. The format is perfect for press releases, search publications, price lists containing product descriptions, training materials, and so on.
If a specialist does not have adequate knowledge in HTML programming, then the PDF format will be a quick and easy way to publish content online.
2. The files contain metadata. PDF files already contain metadata. You can edit the description and add keywords in the “Properties” section, “File” in Adobe Acrobat.
Although metadata does not have a substantial impact on search engine rankings right now, you can create relevant descriptions. In SEO optimization, it is better to consider as many factors as possible to earn high positions in the search results. Read a useful article on the topic: Meta Tags for SEO.
3. It contains URLs. Just like regular web pages, PDF files contain links. You can also insert anchor text in the content.
The Disadvantages of Content in PDF Format
Even though Google indexes PDFs, this format does not contain enough data for analysis and ranking. It worsens the output results, and optimizers have to make more of an effort to improve their positions. Here is a list of the major disadvantages of the PDF format:
- If there is no metadata, the document looks worse to search robots than a standard web page. And although the search engine will perform indexing, the benefits for the promotion of this document will probably be lower than normal.
- Internal links in PDF files are less effective for promoting other content. URLs in documents of this format are not processed by the search engine, as on HTML pages. Additionally, the format does not support nofollow, UGC, or sponsored links.
- There is no navigation. In most cases, PDF files do not have navigation elements, which makes it much more difficult for users to find the information they need. Searching phrases or individual words in PDFs is done using the Adobe Acrobat toolbar.
- A PDF is more difficult to format than a web page.
- It is more difficult to track performance indicators. In most cases, specialists use Google Analytics. The code of this analytical system is a web page tag that is automatically loaded into the database when it is loaded. And when a user opens a PDF file, the page does not load, so the system does not track the transition. You have to install additional plugins or use other services. Here is an article on the topic: Guide to Google Analytics.
- It is not adapted for mobile devices. PDF files are displayed the same way on all devices, and given Google’s Mobile-First Index, such content will not always be a priority in search results. To learn more information on this subject, read the articles: Mobile Search and Mobile-First Indexing.
- The content is scanned less frequently. Since PDF files are rarely updated, search robots do not scan them as often as other pages.
Using PDF files is not the best option for SEO promotion. They are difficult to optimize to get into the top 10 search results, lack some important SEO elements, as well as the other disadvantages stated above. But the main disadvantage is that they are slow to load. The files typically contain many images, graphs, and so on, meaning that users have to wait for them to open. It increases the number of rejections, which can negatively affect ranking. Read more on the subject in the article: What is a Good Bounce Rate?
However, there are many cases when this content format is preferable for users; for example, if technical documentation or other similar information is published. It is often more convenient to download the content to your device or print it out immediately.
10 Tips on How to Optimize PDF for SEO
We have prepared instructions on how to optimize PDF online so that the search robot can index the content correctly.
1. Creating high-quality and useful content
The availability of high-quality and useful content is a critical ranking factor. Technical documentation, training literature, instructions, and so on are all in demand among users.
Many people use PDFs on Google to make it easier to download or immediately print information. Thus, finding relevant topics can lead to a high percentage of clicks and improve the ranking in search results.
2. Optimizing meta tags
Although meta tags do not directly affect them, based on the ranking results, they can create a snippet that is attractive to the user to increase the number of clicks. Additionally, if you assign a PDF title, the title itself will appear in the search results.
Use Adobe Acrobat to edit the file. To make changes, open the properties tab and click on “description” or “tags”, depending on the version. You will see a menu of tags that are available for filling in.
Example of filling in meta tags in a PDF file.
4. Choose the correct file name
In most cases, the name of PDF files consists of numbers and letters, so search robots are not able to understand what the document is about. Also, it directly affects the quality of the URL and is one of the main ranking factors. So include relevant search phrases in the file name so that the bot can index and display them in SERP results.
5. Use the alt tag for optimizing images
We recommend filling in the alt tag for images so that the search robot can identify their content. It is another way to improve the file rating if the user requests data via image search.
You can make changes to the image description in the “Tags” section located in the toolbar.
Read more on the topic in the article: SEO Images.
6. Add headers and level them
The presence of headers simplifies the perception of the material. If it is convenient for users to work with the file, it will help reduce the bounce rate, which helps to improve the ranking in search results.
You can assign a level to headers in the Pro version of Adobe Acrobat. To do this, go to the “Tags” section on the toolbar, and when you find the desired section of the text, click the “Tag” button. The properties section opens, and you can select the header level from the list.
For more helpful information on the topic, see the article H1 Tag: How To Create a Great Header.
7. Linking to a PDF file
PDF files usually contain quite specific information that users do not often search for on the site. However, it might be useful, so we recommend adding internal links to the document, which can have a good effect on the ranking results.
For proof, here is a quote from a 2016 interview with Google employee John Mueller:
In other words, the presence of internal links to PDF files will signal to the search robot that this content is useful and needs to be indexed and evaluated.
Even though the presence of a link is no longer a significant ranking factor, its presence increases the chances of improving your position in SERP. There is more important information in the article What is the SERP in 2020?
8. Make the content more readable on mobile devices
We have already written that PDF files cannot be optimized for mobile output, but this does not mean that you cannot improve the appearance of the text to make it more user-friendly.
Align the text to the left side of the page, this makes it easier to scroll content on a mobile device, and the user does not need to scroll text horizontally. You can also emphasize important sections of text in bold or use colored highlights.
Structure the text using subheadings. This way, the material will be easier to read from mobile devices. The paragraph should contain no more than 4-5 sentences.
This way, you can improve your behavioral factors. There is no reliable information about how much they affect page ranking. But the time spent on the site is one of the signals for the search engine for how authoritative and useful the information is for users.
9. Compress images
The speed of content loading is one of the main factors for ranking. But PDF files are quite heavy, especially if they contain a lot of images. To improve speed indicators, we recommend compressing images, charts, and so on.
You can use JPEGmini or Soda PDF to compress images. They help reduce the size without losing quality.
10. Do not duplicate content
Set the canonical tag in one of the blog posts. It will help you avoid duplicate content. Read more in the article Rel=Canonical Tag.
How do I collect statistics on PDF views?
As we have already mentioned, PDF content is more difficult to track. It is why many marketers grant access to files after the user fills out the form. This way, you can control how much of the information the audience is interested in, but this leads to a shift in focus from tracking the number of views to lead generation, which is not at all effective for SEO.
We offer several alternative ways to collect statistics on PDF views.
1. Track events
You can track the number of clicks on a PDF file in the analytics system. To do this, use the detailed instructions.
2. Use the PDF tracking plugin
The PDF Analytics plugin works with WordPress. It helps you track user traffic in Google Analytics.
You need to download the file in ZIP format, and upload it to the site, open the “Plugins” tab — “Add New”– “Upload.” Then click the “Activate” button. The system will send a message about successful installation with a link to the page with further settings. You can also find it manually in the control panel: “Settings”- “PDF Analytics.” After completing all the instructions, you will be able to track your data in Google Analytics.
3. Use a tracking script
The tracking script will send full information about clicks to your analytics system.
4. Use special tools
You can use Google Search Console or SEMrush to track conversions to PDF files. There is more information in the article What is Google Search Console. The second tool provides information about competitors. You can see what content in the PDF gets more traffic to make changes to the content strategy or better optimize the file. To do this, insert the competitor’s domain in the search bar in the Organic Research section and then open the Pages report. It will contain the URL to the PDF.
So, most SEO optimizers tend to use PDFs less often for search engine rankings. Many experts consider this format to be outdated since it cannot be adapted for mobile devices; it loads more slowly, and so on. But in some cases, this type of presentation is preferred more by users. Thus, it makes sense to correctly optimize the content in a PDF to increase the position in search results.