The sizes for beds follows a precise standard to ensure compatibility across manufacturers of mattresses and bed frames. Consumers can feel free to select a bed size based on their needs and/or preferences, knowing that the size they pick will be in line with the measurements they can expect.
Bunk Beds and Twin Mattresses
Bunk beds and standard twin mattresses are identical in length at 75 inches long. Extra long twin mattresses are 80 inches long. Bunk bed mattresses can be found in a narrow size that measures only 36 inches wide while all other standard bunk and twin mattresses have a width of 39 inches. Twin and bunk sizes are often used for children's beds as they are narrower than other sizes and identical to common kid-themed bedding. Extra-long twin mattresses will require specific bedding to match the slightly longer mattress.
Full and Double Beds
Full and double beds come in standard sizes measuring 54 inches wide and 75 inches long. Full size mattresses are large enough for adults, offering more width than the standard size twin and bunk bed mattresses. Queen size offers the necessary width to accommodate more than one person.
Queen size mattresses come in four standard sizes. The regular queen mattress is 60 inches wide and 80 inches long, able to accommodate two adults. More room is available with California queen mattresses, which offer 84 inches in length for taller adults. The expanded queen mattress keeps the 80-inch length of the regular queen while adding 6 inches across for a width of 66 inches. Super queen matches the width and length of the expanded queen mattresses but are commonly thicker.
The largest class of mattresses are king size. Standard king mattresses are a full 10 inches wider than the widest queen bed at 76 inches. The standard king matches the queen, expanded queen and super queen in length, measuring 80 inches long. California king mattresses come in a bit narrower than standard king (72 inches) while offering greater length (84 inches). The most spacious of all standard mattresses sizes is the grand king. Measuring 80 inches wide and 98 inches long, the grand king is large enough to fit two tall adults with room to spare.