Mattress Size Guide: Dimensions, Room Sizes and How to Choose

Picking the wrong size is the most expensive mattress mistake. Here are the real dimensions, room requirements and who each size suits.

The right mattress size depends on three things: how many people sleep in the bed, how tall they are, and how much room the bedroom actually has. Here are the standard US sizes side by side, followed by how to choose between them.

Standard mattress dimensions

• Twin: 38 × 75 inches
• Twin XL: 38 × 80 inches
• Full (Double): 54 × 75 inches
• Queen: 60 × 80 inches
• King: 76 × 80 inches
• California King: 72 × 84 inches
• Split King: two Twin XL mattresses, 76 × 80 inches combined

Thickness is not standardized. Luxury mattresses commonly run from about 10 to 16 inches, so check your frame, headboard and sheets as well as the footprint.

How much room do you need?

Leave at least two feet of walking space on the sides and foot of the bed, plus space for a door to open and drawers to slide. As a rough guide, a Twin XL fits a 7 by 10 foot room, a Full fits about 9 by 10, a Queen about 10 by 10, and a King, California King or Split King about 12 by 12. Measure the room, mark the bed footprint on the floor with painter's tape, and walk around it before you decide.

Width per person matters most for couples

On a Full, each of two sleepers gets about 27 inches of width. On a Queen it is 30 inches, and on a King it is 38 inches, which is the width of a Twin XL each. If you or your partner move a lot, run warm and spread out, or share the bed with children or a dog, the jump from Queen to King is usually the most noticeable upgrade you can make.

Length matters for tall sleepers

Most sizes are 80 inches long, but a Full and a Twin are only 75. A California King is 84 inches, which is why it is popular with people over about 6 feet 2 inches. If your feet hang off the end of your current bed, look at a Twin XL (solo), a Queen or King at 80 inches, or a California King at 84 inches.

Which size for which situation

• One adult in a small room: Full or Twin XL
• College dorm: Twin XL (most dorms use it, but confirm with your school)
• Couple in a standard primary bedroom: Queen
• Couple who want space, or a family bed: King
• Tall sleepers or long, narrow rooms: California King
• Couples who want independent adjustable bases: Split King

Don't forget the path to the bedroom

Mattresses do not fold, and a large hybrid can be hard to move around tight stair turns, narrow hallways and small elevators. Measure the path from the front door to the bedroom. If access is tight, a Split King or a pair of Twin XLs is far easier to move than a single King.

Bedding and frames are size-specific

King and California King sheets are not interchangeable, and Split King setups need two Twin XL fitted sheets. Frames, mattress protectors and toppers are all sized to the mattress, so confirm the label when you shop.