A bunk bed is a type of bed in which one bed frame is stacked on top of another, allowing two or more beds to occupy the floor space usually required by just one. They are commonly seen on ships, in the military, and in hostels, dormitories, summer camps, children’s bedrooms, and prisons.

Bunk beds are normally supported by four poles or pillars, one at each corner of the bed. A ladder or stairs is used to get to the upper bed, which is normally surrounded by a railing to prevent the sleeper from falling off. Some models also have a privacy curtain for the lower bunk. Because of the need for a ladder and the height of the bed, the top bunk of a bunk bed is not recommended for children under six years of age.

A loft bed is an elevated bed similar to a bunk bed, but without the lower beds, freeing floor space for other furniture, such as a desk, which might be built into the loft bed. Low loft beds are lower to the ground and designed for younger children.