Standard US mattress sizes run from Twin at 38 by 75 inches up to California King at 72 by 84 inches. The most popular sizes for adults are Queen (60 by 80) and King (76 by 80). Pick based on who sleeps in the bed and how much floor space your room can spare, leaving about two feet to walk on each side.
| Size | Dimensions (inches) | Best for |
|---|---|---|
| Twin | 38 x 75 | Children, small rooms, bunk beds |
| Twin XL | 38 x 80 | Taller teens, dorm rooms |
| Full (Double) | 54 x 75 | Solo adults who want extra width |
| Queen | 60 x 80 | Most couples, guest rooms |
| King | 76 x 80 | Couples who want maximum space, co-sleeping |
| California King | 72 x 84 | Tall sleepers, narrower but longer rooms |
| Split King | Two of 38 x 80 | Adjustable bases, couples with different needs |
Two questions settle most decisions. First, who sleeps in the bed? A solo adult is comfortable on a full or queen, a couple is happiest on a queen or king, and couples who share with children or pets should look at a king or split king. Second, what does the room allow? Measure the floor and leave roughly two feet of clearance on each side you need to walk, plus room for the door to open and any side tables.
A standard King is wider (76 inches) and a California King is longer (84 inches) but narrower (72 inches). Choose California King only if a sleeper is very tall or the room is long and narrow. For most couples, the extra width of a standard King is more useful than the extra length. See our best king mattresses for options in both.
Once you have your size, match it to the right feel with our firmness guide, or start from the beginning with the mattress buying guide.
Queen is the most popular size in the US. It fits most bedrooms and gives a couple enough room without dominating the space, which is why it is the default for guest rooms too.
Yes, a queen comfortably fits two adults, though each person has about 30 inches of width, similar to a twin. Couples who want more personal space, or who share the bed with kids or pets, usually prefer a king.
Standard sizes are consistent within an inch or so across US brands, but thickness varies a lot, from around 8 inches to over 14. Always check the height if you use fitted sheets with a shallow pocket or a low bed frame.