The key EPUB vs. PDF difference is that EPUB uses a flexible, reflowable layout for digital reading, while PDF preserves a fixed layout for consistent viewing, sharing, and printing. This core distinction influences each format’s file size, compatibility, interactivity, editability, and security. In turn, choosing the wrong format can lead to several issues, such as excessive zooming on small screens or content breaking into awkward flows.
In this guide, we will explain EPUB vs. PDF differences in more detail and cover common use cases for both formats to help you choose the best one for your needs.
Key Takeaways
- An EPUB file uses reflowable text to adapt to different screen sizes and devices, making it suitable for reading long-form content like e-books and textbooks.
- A PDF file is a digital document format that preserves layout, formatting, and design so the content looks the same across devices and when printed.
- EPUBs are typically smaller than PDFs, which makes them a better choice for sharing and storage; on the other hand, they don’t have the same universal compatibility and consistency as PDFs.
- To decide whether EPUB or PDF is a better fit, you should think about whether consistent formatting, printing, sharing, or flexible digital reading is the priority.
- If you want to distribute content through e-book platforms with account-based DRM, EPUB is often the preferred format; PDF is suitable for creating documents to collect signatures or apply them.
What Is an EPUB File?
An EPUB (Electronic Publication) is a flexible file format for e-books, which stores text, images, fonts, stylesheets, tables, etc. It was developed by the International Digital Publishing Forum (IDPF) in 2007 for digital reading.
The most recent version of this format is the EPUB 3, which supports HTML, CSS, SVG, and interactive elements, such as audio, video, animations, and hyperlinks. This is the reason why EPUB is commonly used for multimedia-rich reading materials, including textbooks and manuals.
Advantages of the EPUB Format
EPUB file format offers several advantages, including:
- Adjustable to any screen size. It automatically fits the screen regardless of the device (e.g. e-reader, phone, tablet, laptop, computer). This means you can read without manually resizing or scrolling sideways.
- Reflowable content. This improves both readability and accessibility by allowing users to adjust the font size, style, spacing, and colors and screen readers to navigate headings, lists, tables, and images.
- Open standard. You can use EPUB across different e-readers, apps, and platforms. Additionally, it includes DRM (Digital Rights Management) options, making it easier for publishers to protect their intellectual property.
What Is a PDF File?
A PDF (Portable Document Format) is a universal file type that ensures consistent document display, regardless of where or how it is viewed. Currently, PDF is an open standard, maintained by the International Organization for Standardization (ISO).
That said, there are different PDF standards, such as:
- PDF/A (ISO 19005) for archiving
- PDF/VT (ISO 16612) for printing large volumes of documents with variable data
- PDF/X (ISO 15930) for reproducing prints
- PDF/UA (ISO 14289) for universal accessibility and assistive technology
- PDF/R (ISO 23504) for multi-page raster-image documents
- PDF/E (ISO 24517) for engineering workflows
Given its preservation purpose, PDFs are commonly used for official documents, contracts, resumes, and reports in professional and legal settings. This is why you will often find contracts, invoices, affidavits, and NDAs saved as PDFs.
Advantages of the PDF Format
This file format comes with several advantages, such as:
- Universal compatibility. PDFs can be opened on virtually any device or operating system—Windows, macOS, Linux, iOS, and Android—without formatting issues.
- Consistency across devices. It preserves the original layout, fonts, images, and spacing exactly as intended, regardless of screen size or platform.
- File safety. PDF offers different security features, such as password protection, encryption, and certification, which help prevent unauthorized access, copying, or tampering.
EPUB vs PDF: Key Differences Explained
The table below outlines the key EPUB vs. PDF differences in terms of layout, file size, compatibility, interactivity, editability, and security:
Aspect | EPUB format | PDF format |
|---|---|---|
Layout | Flexible layout with reflowable content that adapts to different screen sizes and devices | Fixed layout that keeps page margins, fonts, spacing, and over formatting intact |
File size | Generally smaller, so files take up less space and load quickly when storing or sharing | Generally larger because all the elements, including high-resolution images, are preserved |
Compatibility | Requires dedicated reading devices or apps | Can be opened on almost all devices, operating systems, and software |
Interactivity | Supports interactive elements due to being built on HTML and CSS, but these are still device-dependent | Supports interactive elements like clickable links, bookmarks, annotations, fillable fields, buttons, and multimedia |
Editability | Ideal for ongoing content revisions, which affect how content reflows on different devices | Ideal for making edits without altering the document’s original format, like adding annotations |
Security | Handled by the e-book platform, so protection varies widely | Built-in, file-level controls like password protection, encryption, and certification, so security is more robust |
Now, let’s take a closer look at each aspect of EPUB vs. PDF comparison:
#1. Layout
The key EPUB vs. PDF format distinction in terms of layout is that one is fixed, while the other isn’t. With PDF, the page size, margins, fonts, images, etc., are locked in place, and content remains consistent.
In contrast, these elements adapt to the screen size and settings in EPUB files, which makes reading more comfortable on mobile devices. However, the trade-off is less control over how the document displays.
Ultimately, PDF is preferable when you need a precise visual presentation, such as for project proposals, catalogs, and print-ready documents.
#2. File Size
Regarding EPUB vs. PDF file size, the latter tends to be larger because it preserves the original layouts and images and embeds fonts.
On the other hand, EPUBs store content as structured text with separate styling and handle images and fonts more efficiently. They typically load fast and take up less space, even with text-heavy documents like textbooks and manuals.
However, it is easy to compress PDFs without losing quality if you need to reduce their file size.
#3. Compatibility
Both formats have been around for a long time and are well-known, but PDF is effectively universal while EPUB support is more fragmented.
You can easily open PDFs on desktops, laptops, tablets, and smartphones using built-in viewers, free apps, or browser-based editors, such as PDF.net. However, you might need a reader (e.g., Kobo, Nook, or PocketBook) or an app (e.g., Apple Books or Google Play Books) to access EPUBs.
For this reason, PDF is the safer choice for sharing, especially in professional situations. Your recipients won’t need to install specific apps or use dedicated reading devices.
#4. Interactivity
When comparing EPUB vs. PDF quality in terms of interactivity, PDF offers more consistent and predictable results. They support clickable links, bookmarks, annotations, fillable forms and fields, buttons, and multimedia.
On the other hand, EPUBs can include interactive elements because they are built on HTML and CSS. Links, internal navigation, and multimedia are supported, but how these behave depends on the device used. Therefore, you can’t guarantee a consistent experience for all your readers.
#5. Editability
It is fairly easy to edit both EPUB and PDF files. However, the latter is better for controlled edits, meaning changes that are made within a fixed layout without altering the document’s structure, spacing, or overall visual presentation.
For example, filling out forms, adding highlights, comments, and annotations, and modifying text. Thus, PDF is the better format for documents like invoices, contracts, study notes, reusable templates, etc.
EPUB’s editing capacity differs because it is built on HTML and CSS. You can make deeper content-level changes, such as rewriting sections and restructuring chapters. However, these will affect how content reflows on different devices.
#6. Security
There are many ways for you to protect a PDF, including setting a password, restricting actions such as editing, copying, or printing, applying digital signatures with certifications, and configuring expiration dates for time-limited access. These are attached to the PDF itself, so the format is suitable for sensitive documents like financial records, contracts, and other legal agreements.
In comparison, EPUB’s security is usually handled through DRM systems applied by e-book platforms. This means access control relies on the app or device rather than the file. As a result, protection varies widely, and once an EPUB is outside its original ecosystem, restrictions may no longer apply.
When to Use EPUB Files
You should use EPUB files when you are sharing long-form content and want to provide a comfortable digital reading experience. Thanks to its flexible layout, it is ideal for e-books, textbooks, and educational materials that are meant to be read over time.
EPUB files are typically smaller than PDFs, so they also work well for digital distribution. For example, they are easier to download, store, and share when you need to send weekly reading assignments to hundreds of students as a professor.
Additionally, you may choose EPUB when you want to control content access at the account level, rather than relying on file-based safeguards like those commonly used with PDFs. For instance, when you sell a licensed literature textbook and need to prevent unauthorized sharing.
However, EPUB is not always the best choice. Because the format prioritizes flexible reading, it offers less control over exact layout and is not suitable for documents that need a consistent visual presentation for sharing or printing.
When Is It Better to Use PDF Files?
It is better to use PDF files when you want documents to look exactly like they were created, regardless of what is being used to view them. PDF is also preferable for materials that will be printed or formally shared, like proposals, reports, resumes, contracts, and catalogs.
If you need to create templates or fillable forms to collect signatures, PDF is a more practical choice, as it supports interactive form fields while preserving formatting and offering security features that help meet compliance requirements.
However, PDF files can be larger than EPUBs, so they are less ideal when you need to distribute text-heavy content frequently or optimize for mobile downloads and storage.
Get More Out of PDFs With PDF.net
To make the most out of PDFs, you need a reliable editor. PDF.net offers a wide range of tools for you to convert, compress, merge, split, sign PDFs, and more.
If you choose to work through e-books in PDF form rather than EPUB, our handy annotating and AI-powered features (Chat PDF and Summarize PDF) can help you review the content efficiently.
Final Thoughts
Now that you understand the key EPUB vs. PDF differences, you can choose the format that best fits your needs. Thanks to its flexible layout and smaller file size, EPUB is better suited for long-form reading and for distribution through e-book platforms.
Meanwhile, PDF, with its preservation-focused purpose, is preferable for documents that require consistent formatting, printing, or formal sharing. It is also the practical choice for collecting or applying legally binding signatures.
EPUB vs. PDF FAQs
#1. Are EPUBs safer than PDFs?
EPUBs are not inherently safer than PDFs, as they both have vulnerabilities that can be exploited. The level of protection depends more on how the file is distributed and secured than on the format itself.
#2. Can a PDF reader open EPUB files?
A PDF reader can’t open EPUB files by default; you will need to use a compatible e-book reader or app, such as Apple Books or Google Play Books, to open EPUB files.
#3. Can PDFs include interactive elements like EPUB?
Yes, PDFs can include interactive elements like EPUB, including clickable links, form fields, annotations, and multimedia. Unlike the EPUB format, however, they are generally more consistent across readers and devices.