Adobe's PDF is the acknowledged king of document formats, and is a great way to share anything from simple text notes to multi-page reports or a professionally laid-out book, complete with embedded audio and video.
Google's own PDF Viewer offers a simple and standard way to open PDFs on an Android device, but lengthy load times and a near total lack of features could leave you looking for an alternative.
Fortunately, there's no shortage of options. Adobe, Foxit, Gaaiho and other specialist PDF developers now offer very capable viewer apps, sometimes with the same kind of annotation and sharing options that you'll see on the desktop, and in many cases they're entirely free. Keep reading for our pick of the five best Android PDF readers around.
- We've also highlighted the best free PDF editors
Browse the Google Store for PDF readers and you'll find what appears to be a huge choice of apps, but all isn't quite as it seems. Many are very limited, with only the most basic functionality.
Xodo PDF Reader stands out from the underpowered masses for the range and depth of its feature set. Despite its name, the app isn't just about PDF reading: you can also create new PDFs via your camera, from images or Office documents. You can fill in, save and send PDF forms, or highlight text and add annotations of your own. It's even possible to collaborate on your document with others via Xodo's connect service (no registration required).
Supporting features include smart integration with Dropbox, Google Drive and OneDrive. That's not just about providing an easy way to import documents from the cloud: Xodo can also automatically sync your edits with the source file, ensuring it always has the very latest version.
There's another neat extra in Xodo's File Manager. Thumbnail previews and a Recent Files list give you speedy access to the documents you need, and you're able to freely rename, copy, move or delete any documents.
The core PDF viewing engine is what really matters, though, and Xodo's creation works very well. High zoom factors, page cropping and a full-screen mode help you focus on the content, Night Mode makes for comfortable reading in darker environments and versatile search tools and table of contents support enables drilling down to key areas of the file.
Foxit PDF Reader & Converter is a popular PDF app with more than a million installs recorded on Google Play, and a stellar rating of 4.5.
It doesn't take long to understand Foxit's success. PDFs open quickly, you can control orientation with ease, text reflows to fit and you're able to tweak brightness and change the background to make for comfortable reading in all situations.
Simple annotation tools are on hand to assist in highlighting text, adding notes or drawing on the page, and Foxit's Connected technology enables sharing comments and changes with others in real time.
Form handling is a major plus, with options to fill out and save forms, import and export their data and submit forms via HTTP, FTP and email.
While Foxit's core functionality is free, a number of more advanced features are only available if you subscribe (converting PDFs, combining files, password protection, digital certificates, OneDrive Business support). That's no surprise, but if you're on a budget, keep in mind that some PC-based PDF editors can carry out many of these tasks for free.
Adobe's Acrobat Reader isn't the most powerful of PDF viewing apps, but there's more than enough functionality for most situations, and excellent document compatibility means you should be able to view even the most complex of PDFs as it was meant to be seen.
Open a PDF from the web or share a document from another app and Acrobat Reader quickly displays it in a simple viewer. You're able to scroll around the document, zoom in and out or use simple searches, and everything works more or less exactly as you would expect.
Advanced features include form filling and signing, and you're able to annotate files, highlight text, plus you can add and manage PDF comments.
The app is designed to work with many other Adobe services and products. Some of these are free, including 2GB of cloud storage when you sign up for an Adobe account, and the OCR-powered Adobe Scan app which enables using your device as a PDF scanner, turning receipts, business cards, whiteboards and anything else into searchable, editable PDFs.
The commercial extensions aren't always such good value. Converting files to and from PDF, reordering and rotating pages, are functions that other tools often do for free. Still, you don't have to sign up, and the free app delivers all the viewing functionality that many users will need.
Gaaiho PDF Reader doesn't get nearly as much attention as Adobe, Foxit and the other big-name competition, but with Gaaiho's 20+ years' experience in developing PDF software, it's certainly worth a closer look.
The main viewing engine opens documents at speed and provides a comfortable and flexible environment for reading, adding and managing comments, or checking out any attachments.
Speedy options to add and edit bookmarks ensure that you can mark important areas of any document and speedily return to them later.
Basic annotation tools include the ability to highlight text or draw lines, arrows and assorted simple shapes.
Gaaiho PDF Reader 'only' offers direct support for accessing cloud files via Dropbox, but the ability to add other WebDAV servers gives it a level of flexibility that you won't often find elsewhere.
If there's a problem here it's that Gaaiho doesn't seem nearly as interested in developing its Android app as its other software. As we write, for instance, the reader hasn't been updated for more than 10 months, and even that was only a minor bugfix release. It's still a good app, but we'd like to see a busier release schedule to give us more confidence for the future.
EzPDF Reader is a popular commercial PDF reader (£3.49 or $4.89) from Korean developer Unidocs.
The company sells ezPDF in part on being a 'multimedia PDF viewer', able to play audio, animated GIFs, zipped PNGs and video files embedded in the document (assuming they're compatible with your device.) A well-designed interface makes this a very natural process, especially on tablets, and a demo video on the company website shows you how it works.
The viewer has some unusual touches, starting with a double-page view and an animated page flipping effect. That's not going to win over many business users, but it could be a nice touch for kids reading stories on their tablet.
A strong set of more grown-up extras starts with support for opening ePub documents. EzPDF's form handling features include support for managing form calculations, as well as filling out the form, signing and submitting it via email.
There are a vast number of text selection features. Choose a word, phrase or paragraph and you can copy it to the clipboard, search for it within the PDF, or run a general web search via Google, send the text to other apps, read it aloud, highlight the text, underline it, even check its spelling via integration with the free ColorDict app.
Of course there are all the standard PDF reading features, including thumbnail navigation, bookmark support, multiple zoom options, cropping, rotation and more.
What you won't get here is much in the way of fixes or new features – ezPDF Reader hasn't been updated in 15 months – but it's still a likeable app with some unusual and interesting touches.