Adobe Reader is neither the only nor the best document reader. The best PDF readers are free, versatile, and contain no ads.

The alternative PDF readers presented here run the gamut from minimal, lightweight applications built for nothing more than viewing PDFs to more full-featured applications that include annotations and highlighting. Some applications even include features you won't find in Adobe Acrobat Reader, such as basic PDF-editing tools.

1. Sumatra PDF

Sumatra PDF reader with three open PDF files

Highlight: Most lightweight PDF reader, also available as a portable app.

Sumatra PDF is the best alternative to using your browser as a PDF reader because it's easy on system resources. It's also open source. If you want something even more minimalistic than that, you could download its portable app instead of the desktop version.

Sumatra PDF doesn't have any editing options or other advanced features; it's just a window that loads extremely fast and displays PDFs. It does, however, support tabs, and it's packed with keyboard shortcuts, making it even more ideal for rapidly reading PDFs.

Furthermore, Sumatra supports other types of files, including ebooks in ePub and Mobi format and comic books in CBZ and CBR formats. Want support for more ebook formats? Try one of these dedicated ebook readers for your PC.

Download: Sumatra PDF

2. Foxit Reader

Foxit Reader with three open PDF files

Highlight: The most feature-complete free PDF reader.

Foxit Reader was one of the first mainstream Adobe Reader alternatives. It remains a great option because, among the free PDF readers, it offers the most features, with no strings attached.

You'll notice that an extensive number of editing tabs dominate the interface. They cover a range of advanced options, including text markup, a typewriter option, form handling, digital signatures, and more. Unfortunately, some more advanced options, including shared reviews, are greyed out and only available with a paid license.

One of Foxit Reader's best features is that you can add your own shortcuts to the Quick Action Toolbar in the top left. Right-click anywhere in the toolbar to access all customization options. You can also customize the Ribbon interface.

Foxit Reader managed to pack all those features into a cleaner interface than PDF-XChange Editor. But the feature richness comes at a cost: your system resources. You can, however, download a portable version of Foxit Reader.

Download: Foxit Reader

3. PDF-XChange Editor

PDF-XChange Editor with three open PDF files

Highlight: Packed with features, yet fast.

PDF-XChange Editor offers a bouquet of features, making it great for editing and annotations. And PDF-XChange Editor is free. You can buy a license to unlock pro features, but you can also use those features in exchange for a watermark.

If you find the cluttered look of the toolbar distracting, go ahead and edit it to your liking. Right-click anywhere onto the toolbar to launch a menu for quick changes. Click Customize Toolbars at the bottom to enter a static menu where you can take your time to manage those same options.

While PDF-XChange Editor and Foxit Reader have a similar feature set, we noticed that PDF-XChange Editor used more than twice the resources while viewing the same three documents. Keep this in mind if resource efficiency is a priority.

Download: PDF-XChange Editor

4. STDU Viewer

STDU Viewer PDF reader with three open PDF files

Highlight: One viewer to replace them all, great for navigating multiple documents.

The Scientific and Technical Document Utility (STUD) Viewer is one of the best tools for all your technical documentation, books, and other readings. STDU Viewer supports TXT, Comic Book Archive, PDF, DjVu, MOBI, EPub, several image files, and many more document formats.

STDU Viewer's strong suit is managing multiple different documents at once. Not only can you open documents in tabs and expand a navigation panel, but you can also create and navigate bookmarks and highlights, view thumbnails of your open documents, and split windows to compare different pages within the same document. Another neat feature is that you can invert colors, such as from black on white to white on black, which can reduce eyestrain.

While STDU Viewer doesn't have all the features of PDF-XChange Editor or Foxit Reader, it is a great alternative for those who have to read or refer to a lot of digital documents. And its resource use is extremely efficient.

Download: STDU Viewer

5. Adobe Reader

Adobe PDF Reader with three open PDF files.

Highlight: Simple interface and minimal features.

Adobe's PDF reader remains the de-facto standard. At 105 MB, sans optional offers, it's definitely the heavyweight champion among the readers featured here. It also used by far the most resources, up to 10 times more, while running the same set of documents as all other PDF readers.

On the bright side, Adobe Reader maintains a pleasing interface and isn't overloaded with features. You can comment, fill & sign, and convert to PDF or other formats (export). If you ever run into issues opening a PDF file or filling a form using an alternative PDF tool, you won't suffer too much when you have to fall back onto Adobe Reader.

While you will find options to edit and combine PDF files listed under Tools, these are actually pro features that will set you back at least USD 15 per month.

Download: Adobe Acrobat Reader DC

6. Nitro PDF Reader

Nitro PDF Reader with three open PDF files.

Highlight: Blends into Microsoft Office applications and offers extensive features.

Nitro's interface looks like it was lifted straight from Microsoft Office. And like the market-leading office suite, this PDF reader is rich in features.

Unlike many other free PDF readers, with Nitro, you can fill in forms and sign your documents using your digital ID. You can also add notes, extract images, or convert a PDF to a plain text document.

While Nitro PDF Reader remains free, you can't download the free version. You're forced to download a 14-day trial of Nitro Pro, which will turn in the free reader if you don't activate a pro license.

When the trial expires, you'll lose the ability to convert PDFs into Office formats, use OCR, edit pages (including delete, crop, replace, and reorder), combine multiple files, and redact sensitive information. Keeping those features will set you back $214.

Download: Nitro PDF Reader

Bonus: Read PDFs With Your Web Browser

Whether you're using Google Chrome, Firefox, or Microsoft Edge, your browser already has a built-in PDF reader. It won't have all the features, but using your browser as a PDF reader is a quick way to read PDF documents, and it will save you lots of system resources.

The small footprint and easy access come at a cost. In-browser PDF readers aren't always compatible with all types of PDF. Furthermore, browser-based PDF readers lack advanced features, like form filling, document signing, or annotation. It's a compromise, but for the average user, it's a small one.

Microsoft Edge

Microsoft Edge PDF reader toolbar

In Windows 10, Microsoft Edge is both the default browser and the default PDF reader.

PDF files open in an Edge browser tab. The only thing that distinguishes them from a regular web page is the PDF toolbar at the top. You can search the document, adjust the zoom level, print, and save the file. You can also share the document or add it to your Favorites or Reading List.

Note: Microsoft Edge suffered a PDF exploit back in 2016. This vulnerability has since been patched, but issues such as this are the reason why you should always install security updates.

To change your default PDF reader in Windows 10:

  1. Go to Start > Settings.
  2. Within the Settings app, head to Apps > Default apps, click on Choose default apps by file type, and change the app association of the PDF file extension with an application of your choice. This can be another browser or a third-party PDF reader.
This is a screen capture of Windows 10 choose default app by file type

Google Chrome

Google Chrome PDF reader toolbar

Chrome's PDF interface is similar to Microsoft Edge's. In addition to everything Edge does, you can rotate the document, which is essential on a Windows 2-in-1 or tablet.

If Chrome is your default browser, but you'd rather not have it open PDFs for you, you can disable its built-in PDF reader.

Open chrome://settings/content, expand Additional content settings, scroll to the bottom of the content settings windows, and under PDF Documents, check Download PDF files instead of automatically opening them in Chrome. Make sure you have selected a default Windows PDF viewer.

Mozilla Firefox

Firefox PDF reader features

Among the in-browser PDF readers, Firefox offers the most comprehensive package. In addition to standard features offered in Chrome and Edge, you can expand a sidebar, rotate in both directions, and toggle the hand tool.

To disable the Firefox PDF viewer:

  1. Go to Menu > Options > Applications.
  2. In the Content Type table, find the Portable Document Format (PDF) entry, and select your preferred Action.
screen capture of Firefox PDF reader settings preview in Firefox

While in-browser PDF readers and system default apps are great, sometimes you need more than that. Hence, the market for dedicated PDF readers remains highly competitive. Here are some more alternatives with advanced features.

The Best PDF Readers Do It All

These six apps are the best PDF readers around. But not all needs are the same. Even so, hopefully, one of these PDF document viewers is perfect for you.