An e-reader, also known as an e-book reader, is a portable electronic device that is designed primarily for the purpose of reading e-books and periodicals. E-readers have a similar form factor to a tablet; usually use electronic paper resulting in better screen readability, especially in bright sunlight; and have longer battery life when compared to a tablet. An e-reader's battery will typically last for multiple weeks. In contrast to an e-reader, a tablet has a screen capable of higher refresh rates which make them more suitable for interaction such as playing a video game or watching a video clip.

All electronic paper types offer lower power consumption and better sunlight contrast than LCDs. E Ink displays don't produce any light by themselves, so some models offer a frontlight for reading in dark areas.

Electronic-paper readers come in various sizes. Many small e-readers have display diagonal sizes around 150 or 180 mm (6 or 7 in), while some of the large commercially available readers have display sizes around A5 (257 mm (10.1 in)) or A4 size (364 mm (14.3 in)).

Notes:

Some common hardware is resold in different national markets under various brand names. Below is the list of identical hardware:

See Comparison of e-book formats for details on the file formats.

The most notable formats are:

This list is missing many of the 1st and 2nd generation e-reader devices from the 1990s to 2005.