King sized bed

Bed size refers to the dimensions of a mattress and the names by which standard sizes are called. Beds themselves vary widely in size according to the size of the frame and degree of ornamentation but are sold according to the size of mattress they take. The dimensions and names vary considerably around the world, with most countries having their own standards and terminology. In addition, two mattresses with the same nominal size may still vary slightly in actual dimensions, due to manufacturing tolerances, level of padding, and support type.

Modern manufacturing conventions have resulted in a limited number of standard sizes of commercial bedding for mattresses and box springs. Imported beds vary by country of origin as per the table above.

These dimensions are for the mattress—the actual bed frame will be a little larger in order to fully encompass and support the mattress. The thickness of the mattress may vary considerably.