PDF/X vs. PDF/A: A Guide to Choosing the Right PDF Format

PDF/X and PDF/A are two of the most specialized formats in the PDF family. While both share the same foundations, they serve very different purposes.

If you’ve ever wondered which format is best for your specific task, this guide will help you understand the key differences between PDF/X versus PDF/A.

We’ll also touch on the strengths and limitations of other PDF types, like the standard PDF, PDF/E, PDF/UA, and PDF/VT formats.

We’ll keep it simple. And when we’re done, you'll know which format is right for you for every occasion.

Understanding PDF Formats: PDF/A, PDF/E, PDF/X, PDF/VT & PDF/UA

Let’s start with a quick overview of the different PDF document types. Each format has its own strengths and use cases it’s best suited to.

• PDF - The standard format for everyday tasks, like emailing documents, sharing presentations, or saving reports. It’s versatile, widely supported, and perfect for general use.

• PDF/A - Think of this as the “time capsule” format for long-term archiving. It’s built to keep legal documents, contracts, government records, or personal files accessible into the future, even as technology continues to evolve.

• PDF/E - Tailored for engineering uses, like sharing CAD files, blueprints, drawings, and technical specifications. It’s optimized for professionals in architecture, engineering, and manufacturing, where precision and compatibility are key.

• PDF/X - Perfect for creating print-ready materials like brochures, posters, magazines, and marketing assets. It keeps consistent layout, fonts, and colors exactly as intended, making it the go-to format for graphic designers and print professionals.

• PDF/VT - Designed for variable data printing, which includes personalized print jobs like invoices, direct mail, and marketing materials. It supports dynamic content and high-volume printing without sacrificing efficiency or quality.

• PDF/UA - Built to meet accessibility standards, this format is ideal for eBooks, reports, and public-facing documents. It ensures content is readable for users with disabilities, including compatibility with screen readers and assistive technology.

Each PDF type shines in its own way, but some might seem similar at first glance. So let’s break each down further with a head-to-head comparison.

Key Features Comparison: PDF/X vs. PDF/A vs. PDF/E vs. PDF/VT

Here you can see some of the most common features and content types supported by the different PDF formats.

PDF Type	Main Use Cases	Fonts & Images	Multimedia Content	Hyperlinks	Transparency
PDF/A	Long-term archiving (legal, historical docs)	All elements must be embedded	Not allowed	Not allowed	Limited transparency support
PDF/X	Print-ready materials (brochures, posters, etc.)	Embeds fonts and images for consistency	Not allowed	Not allowed	Supports transparency
PDF/VT	Variable data printing (personalized invoices, mail)	Embeds fonts and dynamic content	Limited support	Allowed	Supports transparency
PDF/E	Engineering files (CAD, blueprints, 3D models)	Supports complex drawings and 3D models	Limited support	Allowed	Supports transparency

As you can see, there’s some overlap in the features allowed with each type, and each PDF format has its niche. Of course you’ve also always got the standard PDF format, which is perfect for everyday document sharing.

Advantages & Limitations: PDF/A vs. PDF/X vs. PDF/VT vs. PDF/E

If you want to choose the right PDF format, you need to understand the strengths and limitations of each type. The table below breaks it all down for you.

PDF Type	Advantages	Limitations
PDF/A	- Self-contained format for long-term document preservation. Readable with future software and systems.	- No multimedia, encryption, and hyperlinks. Interactivity and edits not permitted
PDF/X	- Perfect for high-quality, print-ready output. Ensures fonts, layout, and colors remain consistent for printing.	- No multimedia or hyperlinks supported. Limited use outside of print workflows.
PDF/VT	- Ideal for personalized, high-volume print jobs like invoices. Supports dynamic and variable data printing efficiently.	- Primarily suited for print production workflows. Not commonly used outside of specialized industries.
PDF/E	- Handles complex engineering content like 3D models and CAD files. Optimized for precision and compatibility in engineering tools.	- Less useful for general document sharing or archiving. Limited multimedia support.

PDF/A

Strengths:

• Self-contained format for long-term document preservation.
• Readable with future software and systems.

Limitations:

• No multimedia, encryption, and hyperlinks.
• Interactivity and edits not permitted

PDF/X

Strengths:

• Perfect for high-quality, print-ready output.
• Ensures fonts, layout, and colors remain consistent for printing.

Limitations:

• No multimedia or hyperlinks supported.
• Limited use outside of print workflows.

PDF/VT

Strengths:

• Ideal for personalized, high-volume print jobs like invoices.
• Supports dynamic and variable data printing efficiently.

Limitations:

• Primarily suited for print production workflows.
• Not commonly used outside of specialized industries.

PDF/E

Strengths:

• Handles complex engineering content like 3D models and CAD files.
• Optimized for precision and compatibility in engineering tools.

Limitations:

• Less useful for general document sharing or archiving.
• Limited multimedia support.

How Can I Tell if My PDF/A Is Compliant?

PDF compliance is about making sure that your PDF format conforms to the proper PDF ISO standards. These are internationally accepted ways of ensuring that a given PDF format meets the standards it was created for. For example, you can’t just label a document a ‘PDF/A’ without ensuring the file actually meets PDF/A criteria—like not containing hyperlinks or embedded multimedia.

If you want to check if a document is PDF/A or PDF/UA compliant, one of the most reliable validators is VeraPDF. It’s an open source tool that does take some time to set up. But if you need to regularly validate PDF compliance, it’s a great resource to know about.

Which PDF Format Should You Choose?

You should already have a good idea about the different PDF types and what’s best for you. In case doubts remain, here’s our straightforward recommendations.

Use PDF/X if you’re working on creative projects that require professional printing. It’s perfect for brochures, posters, and marketing materials.

Use PDF/A if you need to preserve documents for decades without worrying about compatibility issues. It’s the standard for legal and archival purposes.

Use PDF/E if you’re sharing technical documents like CAD files, blueprints, or engineering specifications. It’s optimized for precision and compatibility in architecture, engineering, and manufacturing.

Use PDF/VT for high-volume, personalized printing projects like invoices, statements, and direct mail. It supports variable data printing for dynamic, efficient output.

Use PDF/UA if accessibility is a priority. It’s the best format for creating eBooks, reports, and public documents that are compatible with assistive technologies like screen readers.

Now you know the difference between PDF/X vs. PDF/A, along with other specialized PDF file types, and you’re equipped to choose the right PDF format for any job.

Did you also know you can edit and annotate PDF documents online for free? Smallpdf offers user-friendly PDF tools to manage and manipulate PDFs with ease. Give it a try, you don’t even have to sign up.