Standard twin bed mattress dimensions measure 38 inches wide and 75 inches long. The compact size of this single bed makes it an easy pick for children’s bedrooms, college dorm rooms, and other tight spaces and is compatible with most standard twin bed frames and foundations.

A box spring is not always necessary for a twin mattress. Many modern twin bed frames, like platform beds or slatted bases, offer sufficient support on their own. However, a box spring alternative can add height and shock absorption, especially when used with metal frames or traditional beds.

Most bunk beds are designed for twin mattresses, so the answer is usually yes— it makes for a great bunk bed mattress size!

However, some bunk bed models accommodate a twin XL mattress (38 x 80 inches), and others have varied upper and lower bunks, usually with a twin on top and a double bed on the bottom. Before purchasing, make sure to double-check all bed frame dimensions.