E-readers and tablets differ primarily in their design and functionality. E-readers are specifically designed for reading digital books and often feature E Ink screens, which mimic the appearance of ink on paper and reduce eye strain. They are lightweight, have long battery life, and often lack the full range of apps and functionalities available on tablets. Tablets, on the other hand, typically have LCD or OLED screens, offer a wide variety of apps, and can be used for browsing the internet, watching videos, and more, making them more versatile but potentially more distracting for reading.

E-readers are generally easier on the eyes for extended reading sessions due to their E Ink screens. These screens do not emit light directly into the eyes and are designed to reduce glare and mimic the appearance of printed paper, which significantly reduces eye strain compared to the backlit screens of tablets. Tablets, with their LCD or OLED screens, can cause more eye strain over long periods of use, especially if used with high brightness settings.

E-readers typically offer better battery life compared to tablets. Because E Ink screens consume very little power, e-readers can last for several weeks on a single charge, depending on usage. Tablets, by contrast, have more power-hungry LCD or OLED screens and a wider range of functions, which means they usually need to be charged every day or two with regular use.

E-readers are generally more portable and travel-friendly due to their lightweight and compact design. They are designed to be easy to carry around, often fitting comfortably into a bag or even a large pocket. While tablets are also portable, they tend to be heavier and bulkier than e-readers. Moreover, the longer battery life of e-readers makes them more convenient for travel without the need to frequently recharge.

Both e-readers and tablets can be used to read in the dark. Many modern e-readers come with built-in front lights that illuminate the screen without producing glare, making them suitable for reading in low-light conditions. Tablets, with their backlit screens, are also capable of being used in the dark. However, the backlight on tablets can be more straining on the eyes over long periods compared to the front light of e-readers.

Tablets are generally better for reading PDFs and other document formats due to their larger and more versatile screens. Tablets can display color, handle complex layouts, and allow for easy zooming and navigation within documents. While e-readers can handle PDFs, the experience is often less smooth due to smaller screen sizes, slower refresh rates, and the limitations of E Ink technology. Some high-end e-readers with larger screens may offer a better experience for PDFs, but tablets generally remain superior in this regard.