If you're still using Adobe Acrobat Reader for PDF documents, it's time for you to move on. The app is slow, bloated, and comes with too many unnecessary features for most users.

Unless you're a PDF power user, a lightweight PDF app is all you need. A lightweight app will open quickly, won't hog all your system resources, and in some cases, might even be portable.

Here are the best lightweight PDF reader apps that you can use as an Adobe Reader alternative.

1. Sumatra PDF

sumatra pdf

Sumatra PDF is the best option for lightweight PDF reading. It's been around for more than a decade, and it's still actively developed.

It supports several formats beyond mere PDFs that you are likely to encounter regularly, including EPUB, MOBI, XPS, DJVU, CHM, CBZ, and CBR.

The app has three main advantages. First, the EXE file is just 13 MB, which is impressive compared to the 150+ MB of a bloated app like Adobe Reader. Second, it's lightning-fast and can load even large PDF files in a flash. Lastly, the interface is extremely minimal to maximize screen estate. This is wonderful for smaller-screen devices.

It also comes in both portable and installable versions. It's tiny enough to carry around on a USB flash drive of any size, and you'll be able to read PDFs anywhere you go.

Download: Sumatra PDF (Free)

2. Slim PDF Reader

slim pdf reader

Slim PDF Reader is a direct competitor to Sumatra PDF. They are the two best light PDF readers on the market.

Some of Slim PDF Reader's key features include support for both light and dark themes (remember, using a dark theme is one of the most important steps you can take to reduce your eyestrain if you spend all day looking at a computer screen), a simple and easy-to-use navigation panel, extensive annotation tools, and interactive form filling and signature verification options.

The size of the EXE file is only 15MB.

Some other cool features of the app are the ability to convert PDFs into other formats (including Word, Excel, PowerPoint, and CAD), and a way to create PDF files from any printable file format.

The only downside of Slim PDF Reader is the lack of a portable version. For many users, that will not be a dealbreaker. However, if you need the feature, you should turn to Sumatra PDF instead.

Download: Slim PDF Reader (Free)

3. PDF-XChange Editor

PDF-XChange Editor

PDF-XChange Editor is the revamped version of the now-discontinued PDF-XChange Viewer.

As the name suggests, the new app has more features than its predecessor, with the most notable change being that the app can now edit PDFs rather than performing solely as a PDF viewer.

Some of the editing features you will now find in the app include annotations, a way to sign PDFs with your signature, the ability to reorder pages in your PDF document, strikeout, and text correction.

You also get a 3D model tree pane to simplify navigation, tags, customizable toolbars, OCR extraction, an eraser tool, and PDF extraction from other printable documents.

Sadly, the app is not entirely free to use. According to the developer, more than 70 percent of the features in the software do not require a license to use. However, the remaining features will insert a small watermark onto your PDF if you use them. That might not be an issue for personal use; however, if you need to use the app in a professional setting, you will probably want to cough up. A single-user license costs a one-time fee of $46.50.

Download: PDF-XChange Editor (Free, premium version available)

4. MuPDF

MuPDF has three core purposes. Of course, it is a PDF reader, but it can also serve as an XPS viewer and an ebook reader. Some other supported formats include CBZ and FB2.

But be warned, MuPDF is not suitable for people who are not familiar with working with the command line. Although the developer has added graphical viewers for all platforms in recent editions, the app is mainly designed for use via command line inputs.

The command line will let you edit PDFs and convert documents (to HTML, PDF, SVG, and CBZ), and you can also use it to create your own scripts for manipulating documents using JavaScript. The library is written modularly in portable C language.

That means this PDF reader is extremely lightweight—the main download only consists of a software library and command-line tools. The viewer downloads are optional and can be grabbed as needed.

Perhaps the biggest benefit of MuPDF is the anti-aliased graphics. Text is rendered to within a fraction of a pixel of accuracy, thus providing some of the highest fidelity you will find.

Download: MuPDF (Free)

5. Nuance PDF Reader

nuance pdf reader

With an EXE file size of 40 MB, Nuance PDF Reader is the largest lightweight PDF reader on the list. If you need an uber small size, you would still be better off opting for Sumatra PDF or Slim PDF Reader.

Nonetheless, the app still comes in well below PDF readers like Foxit (100 MB) and Evince (80 MB). And despite its slightly larger size, it will still open your PDFs in a blink of an eye, so it is definitely a worthy app to consider.

The key features of Nuance PDF Reader include emailing PDFs directly from within the app, displaying multiple pages on your screen at once, PDF conversion (PDF to DOC, DOCX, XLS, and RTF), and basic PDF annotation tools.

Probably the biggest drawback is the lack of an editor, so if you need to tweak the actual contents of your document, you should look elsewhere.

Download: Nuance PDF Reader (Free)

Don't Use These PDF Readers if You Need More Features

Remember, the five apps we have looked at in this article have all been specifically designed by their respective developers to be as lightweight as possible. Naturally, that extremely small footprint comes at a cost in terms of features. That's not to say they are short of features, but people who use PDFs regularly in their jobs might need more power.

If you need more power, you should consider using a fully-fledged PDF editor. Some of the best options available include PDFpenPro 11, Acrobat Pro DC, and PDF Candy.