How to Optimise PDF Files for SEO: Everything You Should Know
Table of Contents
What Are the Main Uses of PDFs in the context of Business sites?
PDF, short for Portable Document Format, is a file format patented by Adobe Systems. This proprietary format presents online users with a convenient way to read electronic documents. You can use PDFs for promotional brochures, short ebooks, guides, product flyers and product catalogues, to provide information on your business website.
This Read Only document format has many advantages, as PDFs are:
- Fast and easy to create
- Highly secure
- Compatible across multiple formats
- Easily compressible
You can include text, images, hyperlinks and plenty more in a PDF file. The best feature of PDFs is that site visitors can view them page-by-page in quick time.
How Do You Rank Web Pages Versus PDF Documents?
PDF documents are longer, more detailed documents and people are less likely to link to them.
Google’s intent with any Search is to serve results that best address the users’ search query. So, the question really is whether a user is better served by Google if they return a PDF document or a web document.
It’s a hard problem for a Search Engine to figure out as the utility and value of one document versus the other are very different. Given that PDF and web documents are completely different data types – it’s really an apples versus oranges comparison.
Google’s take on this issue is that based on what they know about the User, different ranking signals, and availability of different types of information & media in their index , they make their best guess about ranking a PDF versus a Web document.
It’s an imperfect science but they do their best in delivering what they think will be most useful for a user. That being said, a Web document is more likely to rank higher than a PDF in 9 out of 10 cases, but there are definitely instances and opportunities for PDFs to rank higher in certain niches.
Is It Possible for Google to Index Any Type of PDF File?
In general, Google indexes PDF files (written in any language) just as they would index other normal pages on your site. But Google algorithms don’t refresh PDFs as quickly as they would refresh normal HTML pages because they assume these files stay stable.
The rule of the thumb is if the text from your PDF file can be copied and pasted into a standard text document, then Google crawlers should be able to index that text. But Google crawlers will not be able to index PDFs that have a nofollow link.
A default “nofollow” may be an automatic setting in WordPress and other cloud-based CMS platforms such as Wix & Shopify. These platforms don’t automatically index PDF files. This may be easily fixed with the help of a good SEO Consultant or by reading through CMS guidance on PDF files.
Read our Insights on How To Choose a Good SEO Consultant.
Google will also not be able to index PDFs that are password protected, encrypted or not in static HTML. SEO for PDF files requires that you allow crawlers to read and index these files.
How are PDFs shown in Google Search Results?
If your query is transactional or navigational in nature, meaning you’re looking to buy something or get somewhere, there’s minuscule probability that Google will return a PDF result.
However, if your query is informational in nature, Google may return a PDF file. Searching for a guide, academic research papers, or using Google’s filetype operator (“filetype:PDF SEO Audit Checklist”) are some use cases for finding PDF results.
You can instantly notice the PDF results as they’ll be shown with a PDF icon, next to them. The small icon is included next to search results:
How Can You Conduct PDF SEO Optimisation?
When your PDFs are properly optimised for SEO, they stand to rank better in Google Search. They will also add immense value to your site pages.
Outlined here are 11 best practices you should follow for PDF SEO optimisation.
PDF SEO Tip #1: Create Unique Content
While preparing a PDF file, focus on creating unique rich content that is different from your web pages. Google loves good content even if it is not your web pages.
There are many whitepapers, documentation, etc ranking on top of SERPs as some of the best information on the web is actually buried in PDFs.
PDF SEO Tip #2: Title and Description Metadata For The File
While you are working on your PDF title and description, go for keyword research. Determine the best-targeted keyword you can use for PDF SEO.
Consider how many global & local searches Google is reporting per month for your chosen keyword. Then update the PDF metadata including the file description, author’s name, subject, and keywords
The title of your PDF is comparable to an HTML title tag. It will show up in the Search Engine Result Pages (SERPs). Therefore, your title should be SEO optimised – descriptive, under 60 characters and have the primary keyword at the beginning.
Though meta description is not considered a ranking factor, adding an optimised description gives you a shot at controlling the text that shows up in the search results. Keep your description under 160 characters and try to place your primary keyword in the first sentence.
Include the keyword in the file name, subject and URL, as well. Although the other metadata fields are not ranking factors, they contribute to a successful crawl. So when you present bots with more data, you have everything to gain.
PDF SEO Tip #3: Optimise The Document File Name
Apart from the metadata, you should also pay attention to your PDF document file name.
You want to make sure that the PDF file name is keyword-rich and uses some best practices.
Imagine that you are creating a URL when you name your PDF file. For example, you have a PDF titled: ‘SEO Definitive Guide: Everything You Need to Know’
For most CMS’s, the URL slug that gets created and mapped to any website page is defaulted to the page’s title.
You don’t have to use the title as the document name. Instead, you can optimise the document name to something different: ‘seo-detailed-guide.pdf’
Here are some best practices to follow when assigning a name to your PDF document:
- Use lower case
- Avoid lengthy file name. Shorter is better
- Don’t use punctuation or hashes.
- Avoid stop words (a, an, the, and, it, for, or, but, in, my, your, our, and their, etc.)
- Use hyphens or underscores to separate words
PDF SEO Tip #4: Anchor Text of Any Links Pointing to PDF Files
The links from the pages of your website to the PDFs are crucial SEO signals. These links will indicate to Google spiders that the PDFs need to be crawled.
The anchor text will show Google how your PDFs fit within the content of your Business site. There’s another advantage, too. Any backlinks to your PDFs will automatically transfer authority to your web pages via deep links.
However, you’ll need to write-protect your PDFs to prevent the alteration of the links in them.
PDF SEO Tip #5: Internal Links from the PDF File to Your Web Pages
Sending signals by creating internal links to your PDF files is a good idea. But don’t forget that you also need to create internal links from your PDF file to your web pages.
By linking out from the PDF, you’ll help the readers visit the content they want to read on your website. In addition, you’ll also pass signals to Google that the page you linked from the PDF file is an important page.
PDF SEO Tip #6: Header Tags & Content Within the PDF File
Don’t just make your headers bold. Instead, use header tags, such as h1, h2, h3, etc. Headlines help readers to quickly understand the content and structure of your PDF. This styling format will also indicate to search engine spiders how your PDF is structured.
Optimise the content within the PDF by using the keywords you intend to rank for.
In this age of ultra-short attention spans, it’s worthwhile to left align your content and use short paragraphs in your copy.
And use three or four short sentences in a paragraph. You really want to encourage visitors to read your content, don’t you?
PDF SEO Tip #7: Optimise the PDF File URL
From a purely ranking point of view, having keywords in the URL helps SEO for both site pages & PDF files.
The PDF URL is easily editable in self-hosted platforms such as WordPress.
However, a PDF document URL is not editable for cloud-based site builders such as Wix, Shopify and others.
PDF files hosted on Cloud based site builders are directly uploaded to the platform’s host servers, and the URL gets autogenerated.
So, if you’re using WordPress or other customisable Content Management Platforms, include relevant keywords in the PDF URL, separated by dashes. (e.g. “how-to-optimise-for-PDF-SEO”)
PDF SEO Tip #8: Alt Text in PDF Files
Alt text, referred to as alternative text, provides a text alternative for the images in your PDFs. In case the image doesn’t load, the alt text will be displayed to the reader.
The alt tag is the short text description – usually 100 characters or less, that you can assign to an image in your PDF before you upload it to any platform.
Alt text allows visually-impaired users with screen readers to understand the images inside a document. Additionally, these tags allow search engine spiders to crawl your PDFs and rank them.
So, adding alt tags is another relevant element of PDF SEO.
PDF SEO Tip #9: Compressing the PDF Size for Speed
Large file sizes can be disastrous for PDF SEO optimisation. No reader (or search engine) would want to wait for your PDF to load. Maintain a small file size to avoid slow download times.
In newer versions of Acrobat and Reader, you can sidestep this issue by quickly clicking on the Reduce File Size option. This PDF SEO tool reduces file size without compromising on quality.
PDF SEO Tip #10: Optimise PDF Fonts
PDF readers support the below set of standard fonts:
- Zapf Dingbats
Using any of the above standard fonts in your PDF is recommended as any other font might require embedding which in turn increases the size of your PDF.
Also, fewer the fonts you use, the lesser will be the size of your PDF so is the case of font styles.
PDF SEO Tip #11: Optimise PDF for Mobile
With almost everyone used to surfing and consuming information through mobile devices, it is a clever step to optimise your PDF for phones, tablets, etc.
Follow the below steps to make your PDF mobile-friendly:
- Left-align text so that the user won’t have to scroll horizontally
- Use bullet points that help to skim through text easily
- Break content using headings and subheadings
- Use short paragraphs instead of big chunks of text
Is It Possible for PDFs to Rank in Search Engine Results?
Yes, it is possible for PDFs to rank in search engine results. And you can optimise PDFs for higher search rankings. But you have to conduct PDF SEO optimisation following the six best practices outlined above.
When you implement these optimisation strategies, your PDFs will be indexed by the search engines, and they will appear in SERPs.
How Are Links Treated in PDF Files?
Google regards contextual links inside PDFs as a signal to index and crawl them.
In essence, the links to any PDF files on your site will pass on PageRank & link authority to these files. The same applies to links from PDF files to other Site pages.
Note: At the time of this writing, it is not possible to use nofollow links within a PDF document.
How Are Images Treated in PDF Files?
Currently, the images in PDF files are not indexed. However, it’s advisable to use images generously in PDFs.
The reason is images help break up blocks of text. Visitors will then find it easier to skim through and digest your content. Since images tend to increase the size of your PDFs, you need to use them wisely.
Please refer to our blog post Optimise Your Ecommerce Site for Image Search for useful tips on Image SEO optimisation.
How to Make Sure The Correct Title Shows Up for PDFs in Google Search Results?
Google uses two main elements to give its algorithms strong SEO signals regarding the appropriate title to help decide the title for a specific PDF file:
- The Title metadata within the PDF file
- The Anchor text of links pointing to the PDF file
Make sure to leverage both these elements appropriately.
How Can You Track Downloads of Your PDF Files?
To track PDF file downloads, you can add extra code directly into your Site’s Header, use third-party plugins that are available for your Site platform, or use Google Tag Manager.
Is Having The Same Content in Both PDF and HTML Files Considered Duplicate Content?
From a purely technical perspective, the answer to this question is yes. It would be an instance of internal Duplicate Content if a visitor could access the same content on your site via an HTML file, as well as a PDF. Google favours and ranks the HTML version in the event of internal Duplicate Content.
To avoid duplication, make sure to specify the preferred page version, by including it in the Sitemap, or by indicating the canonical version in the HTTP headers of the PDF resource.
How can I prevent my PDF files from appearing in search results?
To prevent your PDF files from getting indexed, you can simply use the X-Robots Tag: noindex to the HTTP header that will serve the file. If the PDF file is already indexed, it will eventually disappear.
Another option you can try is by using the URL removal tools from Google Search Console.
Looking for Help to Fix SEO PDF Issues – We Can Help
At Digital Chakra, we help ambitious small & mid-sized retail eCommerce Businesses get better search visibility through data-driven SEO solutions. We can offer advice & guidance for any SEO PDF issues you may be facing.