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Key takeaways
- Standard US sizes in inches: Twin 38 × 75, Twin XL 38 × 80, Full 54 × 75, Queen 60 × 80, King 76 × 80, California King 72 × 84.
- A Split King is two Twin XLs side by side, which adds up to the same 76 × 80 inches as a standard King.
- A Cal King is 4 inches narrower and 4 inches longer than a King. It's for height, not extra width.
- Leave roughly 24 to 30 inches of walkway on each used side and at the foot of the bed. Add that to the mattress size to check room fit.
- Brands vary by an inch or so, and some list a Full as 53 inches wide. Always check the exact dimensions in the listing before buying sheets or a frame.
US mattress sizes at a glance
These are the standard US mattress dimensions. Individual brands can differ by an inch or so (some list a Full as 53 inches wide, for example), and foam mattresses can vary slightly after they expand. Check the listing for exact numbers.
| Size | Width × length (inches) | Surface area (sq in) | Best for |
|---|---|---|---|
| Twin | 38 × 75 | 2,850 | Kids, bunk beds, daybeds |
| Twin XL | 38 × 80 | 3,040 | Teens, dorms, tall single adults, split kings |
| Full (Double) | 54 × 75 | 4,050 | Single adults, guest rooms |
| Queen | 60 × 80 | 4,800 | Couples, the most common size |
| King | 76 × 80 | 6,080 | Couples who want space, families |
| California King | 72 × 84 | 6,048 | Tall sleepers |
| Split King | Two 38 × 80 | 6,080 total | Couples with different needs or adjustable bases |
Each size in more detail
Twin (38 × 75)
The smallest standard adult mattress. It's the default for kids' rooms, bunk beds, trundles and daybeds. At 75 inches long, it's short for many adults and teens.
Twin XL (38 × 80)
Same width as a Twin, 5 inches longer. It's the standard for college dorms, so check before buying dorm sheets. It's also the building block of a Split King. A good pick for a single adult in a small room who's too tall for a Twin.
Full, or Double (54 × 75)
Sixteen inches wider than a Twin, same length. A comfortable bed for one adult, and a common guest-room size. For two adults it's tight: each person gets 27 inches, less than a Twin's width. It's also 75 inches long, which is short for taller sleepers. Some brands offer a Full XL (54 × 80), but it's uncommon and sheets are harder to find.
Queen (60 × 80)
The most popular size in the US. It fits most bedrooms and gives a single sleeper plenty of room. For couples it's 30 inches per person, which works for many but gets crowded fast with pets or kids. Queen sheets, frames and accessories are the easiest to find. Some brands also sell an Olympic Queen, about 66 × 80, but sheets and frames for it are specialty items.
King (76 × 80)
Sixteen inches wider than a Queen, same length. Each sleeper gets 38 inches, the same as a Twin XL. It's the most comfortable size for most couples, as we cover in our mattress guide for couples. The trade-off is room size and cost of bedding.
California King (72 × 84)
Four inches narrower and four inches longer than a standard King. It's often chosen for tall sleepers, and it can suit rooms that are longer than they are wide. It is not a "bigger King." Its surface area is actually slightly smaller. Cal King sheets and frames aren't interchangeable with standard King.
Split King (two 38 × 80 Twin XLs)
Two Twin XL mattresses side by side on a King frame, adding up to 76 × 80 inches. Couples choose it for two reasons: each person can pick a different mattress, and each side of an adjustable base can move independently. It uses split King sheets (or two Twin XL fitted sheets under a King flat sheet). See best adjustable bed bases for split-king bases.
A Split California King exists too, made of two 36 × 84 mattresses. It's less common and needs specialty sheets.
Width per sleeper: the number that matters for couples
Divide the mattress width by the number of people sleeping in it.
| Size | One sleeper | Two sleepers |
|---|---|---|
| Full | 54 in | 27 in each |
| Queen | 60 in | 30 in each |
| King | 76 in | 38 in each |
| California King | 72 in | 36 in each |
For reference, a Twin is 38 inches wide. So on a King, each partner has the width of their own Twin. On a Full, each partner has less than that. If you share a bed with a pet or a child, subtract the space they take before deciding.
Length: will your feet hang off?
A common rule of thumb is to choose a mattress at least a few inches longer than your height, so there's room for a pillow and your feet.
- 75-inch beds (Twin, Full) are 6 feet 3 inches long.
- 80-inch beds (Twin XL, Queen, King) are 6 feet 8 inches long.
- 84-inch beds (Cal King) are 7 feet long.
If either sleeper is over about 6 feet, skip the 75-inch sizes. If someone is well over 6 feet and likes a big pillow, a Cal King's extra length helps.
Room-fit math
A mattress that fits the floor but leaves no room to walk will make the room feel cramped. Use this simple method.
- Pick a walkway width. A common rule of thumb is about 24 to 30 inches on each side you use and at the foot of the bed. Many people treat 24 inches as a comfortable minimum.
- Add it to the mattress width. For a bed you walk around on both sides, add two walkways.
- Add it to the mattress length. Add one walkway at the foot (the head is against the wall).
- Account for the frame. Frames and headboards usually add a few inches to the mattress size.
- Add nightstands if they sit beside the bed, typically 18 to 24 inches wide each, depending on your furniture.
Worked example: Queen in a 10 × 10 foot room
A 10 × 10 room is 120 × 120 inches. A Queen is 60 × 80. Using 24-inch walkways and a 4-inch frame allowance:
- Width: 60 + 4 + 48 = 112 inches. That fits a 120-inch wall, with 8 inches to spare. Nightstands will be tight, so consider small ones or wall shelves.
- Length: 80 + 4 + 24 = 108 inches. That fits in 120 inches of room depth.
Worked example: King in a 12 × 12 foot room
A 12 × 12 room is 144 × 144 inches. A King is 76 × 80.
- Width: 76 + 4 + 48 = 128 inches. That leaves 16 inches for nightstands, which isn't enough for two standard ones. Either use one, choose narrow nightstands, or accept narrower walkways.
- Length: 80 + 4 + 24 = 108 inches. Fits comfortably.
Worked example: Should it be a King or a Cal King?
Say the room is 132 inches wide and 150 inches deep. With 24-inch walkways and a 4-inch frame allowance:
- King: 76 + 4 + 48 = 128 inches wide. Fits with little to spare.
- Cal King: 72 + 4 + 48 = 124 inches wide. Fits with a little more side room, and the extra 4 inches of length is easy in a 150-inch-deep room.
In that room, a Cal King may be the better fit if neither of you needs the extra width and one of you is tall.
Don't forget the path in
Measure door widths, hallway turns and stairwells. Most mattresses now ship compressed in a box, but frames, box springs and adjustable bases don't. King box springs and foundations are often sold as two pieces for this reason.
Choosing sheets and bedding by size
- Match the size exactly. King and Cal King sheets aren't interchangeable.
- Measure mattress depth, including any topper, and buy sheets with deep enough pockets.
- Comforters and duvets are often sold as Full/Queen and King/Cal King combos. See our down alternative comforter size guide for drape and overhang.
- Split Kings need split-top or split fitted sheets, or two Twin XL fitted sheets.
Mistakes to avoid
- Buying a Cal King for more width. It's narrower than a King.
- Assuming a Full works for two adults. Each person gets 27 inches.
- Forgetting the frame and headboard. They add inches you have to plan for.
- Buying sheets by name only. Pocket depth matters as much as size.
- Skipping the delivery-path measurement for frames and bases.
For choosing the mattress itself once you've settled on size, read the complete mattress buying guide and mattress types explained.
Frequently asked questions
What are the standard US mattress sizes in inches?
Twin 38 × 75, Twin XL 38 × 80, Full 54 × 75, Queen 60 × 80, King 76 × 80 and California King 72 × 84. A Split King is two Twin XLs, totaling 76 × 80.
Is a California King bigger than a King?
No. A Cal King is 4 inches narrower and 4 inches longer than a standard King, and its total surface area is slightly smaller.
What is a Split King?
Two Twin XL mattresses side by side on a King frame. Together they measure 76 × 80 inches, the same as a standard King.
What size bed fits in a 10 × 10 room?
A Queen fits a 10 × 10 room with roughly 24-inch walkways on both sides, though nightstands will be tight. A King is usually too wide for comfortable walkways.
Is a Full big enough for two people?
It's tight. A Full is 54 inches wide, which gives each person 27 inches, less than a Twin's width.
What is the difference between a Twin and a Twin XL?
They're the same width, 38 inches, but a Twin XL is 5 inches longer at 80 inches. Twin XL is standard for dorms and split Kings.