An e-book layout format where the text is not divided into pages in advance, but instead is 'flowed' according to the size and shape of the reading device.

This allows the reader to choose the size of the typeface, the margins, and the line spacing. The e-reader then fits the text to their screen based on these choices.

The advantage of a reflowable e-book is that it can be read on any device, regardless of the size, aspect ratio, or orientation of the screen. Reflowable books are also helpful to people with vision impairments.

The disadvantage of a reflowable layout is that many graphic design techniques are not possible because the size and shape of the screen are not known in advance.

Also see: fixed format.