E-readers allow you to carry thousands of books in a single, transportable device. If you're interested in buying a new e-reader, there are styles, specs, and feature sets you should know about.

Here's what to look for in an e-reader.

Screen Type

E-reader displays used to be made with a technology called E Ink. However, tablet computers like the Apple iPad introduced several backlit or LCD e-reader displays. Even E Ink stalwart Amazon launched tablet versions of its Kindle line, the Kindle Fire.

When choosing an e-reader, decide if you prefer an unlit, paper-like display like E Ink or a typical LCD screen like your phone's. Each has advantages and disadvantages. E Ink tends to reduce eye strain and improve battery life. An LCD screen can display color and typically comes with touchscreen capabilities.

There are also hybrid readers, such as the newer E Ink Kindle and the Barnes & Noble NOOK. These e-readers feature both an electronic paper display and an LCD touchscreen at the same time.

For electronic paper displays, compare screens. Some have better contrast and a higher resolution than others.

Size and Weight

Size matters, especially when it comes to how portable you want your e-reader to be. There are all sorts of options when it comes to size. Amazon's basic Kindle or the Barnes & Noble NOOK Glowlight Plus are on the smaller end. Both are light and easy to take with you on the go.

Then there are the larger ones, such as the Kindle Fire HD 10, the Apple iPad, and the iPad Pro. None of those can fit in a pocket. Still, if you want a big screen, these are worth considering.

Interface

E-reading device control is typically based on buttons, a touchscreen, or a combination.

Button-based controls require less power and are more accurate. Still, these controls can be cumbersome to use. Button-based devices include older models such as the Amazon Kindle 1, 2, 3, and DX models, the Sony Reader Pocket, and the original Kobo eReader.

Touchscreens are more intuitive but can be laggy, smudge-prone, and typically drain more battery. Touchscreens are gaining popularity as the interface of choice, even for E-Ink-based displays. The iPad, Kindle Fire, and NOOK tablets use LCD touchscreens. 

These features are essential for younger children and seniors, who sometimes have trouble using devices like this.

Battery Life

Depending on whether you plan to read primarily at home or on the road, battery life is an important consideration. Basic e-readers without fancy features typically have a longer battery life. Devices with Wi-Fi and web browsing tend to have shorter operating times.

Features

Do you want an e-reader to read e-books, or do you want your device to do more? Some devices, such as the older Reader Pocket and Kobo eReader, are designed for reading and skip on extra features, including music playback.

On the other hand, the NOOK plays music, has a web browser, and includes a touchscreen interface. At the higher end of the feature spectrum are tablets like the iPad, which function like a mini-computer.

Formats

You'll also want to check the device's ability to handle file formats. Popular file formats include EPUB, PDF, TXT, and HTML. The more formats a device can display, the better.

Also, check if an e-reader uses an open format or a proprietary format. An open format, such as EPUB, means you can move e-books from one device to another. In contrast, Amazon's proprietary AZW format can only be displayed by Kindle devices, but it can convert EPUB documents using the Send to Kindle app.

Capacity

This determines how much media fits in the device at one time. The higher the memory, the more e-books and files you can fit. High capacity is especially important for multimedia e-readers that also play music, video, and apps.

Besides internal memory, some devices come with a slot for an SD card, which allows you to bump up the device's capacity.

Store Access

Depending on the device, an e-reader can directly access certain e-book stores, which means extra convenience, a more comprehensive selection, and access to the latest bestsellers.

The Kindle, for example, has direct access to Amazon's online bookstore, while the NOOK and Kobo have access to Barnes & Noble and Borders, respectively.

Devices without direct store access can still display compatible e-books, but you must download the books from a PC first. Free e-book sources like Project Gutenberg are another option.

Price

This can be the most significant factor when buying an e-book reader. Analysts and industry insiders have said that$99 is the magic price point for most e-readers. There are several options in that price range.

In the early 2010s, many e-readers had price tags over$400. These days, that's enough to buy a tablet.