Discover Your Perfect Mattress Size
Last updated: June 2026
There are seven common mattress sizes in the U.S.: Twin (38" x 75"), Twin XL (38" x 80"), Full (54" x 75"), Queen (60" x 80"), King (76" x 80"), California King (72" x 84"), and Split King (two Twin XL mattresses, 76" x 80" combined). The right size depends on who's sleeping, the room you have, and whether you want an adjustable base. Twin and Full suit solo sleepers and smaller rooms; Queen is the most popular size for couples; King and California King give two people the most room, with California King trading width for extra length; and Split King is the size to choose for an adjustable bed two people share. The full dimensions chart is below.
Mattress size dimensions chart
| Size | Dimensions (W x L) | Best for | Suggested room |
|---|---|---|---|
| Twin | 38" x 75" | Children, single sleepers, small rooms | 7' x 10' |
| Twin XL | 38" x 80" | Taller solo sleepers, dorms, split adjustable setups | 7' x 10' |
| Full (Double) | 54" x 75" | Solo sleepers wanting more width; occasional couples | 9' x 10' |
| Queen | 60" x 80" | Couples; the most popular size | 10' x 10' |
| King (Eastern King) | 76" x 80" | Couples wanting maximum width, room sharers | 12' x 12' |
| California King | 72" x 84" | Taller sleepers; longer, narrower rooms | 12' x 14' |
| Split King | 76" x 80" (two 38" x 80") | Couples on an adjustable base who want independent sides | 12' x 12' |
Notes on the less obvious sizes
Twin XL is the same width as a Twin but five inches longer, which makes it the better choice for a growing teen or a taller adult who doesn't need the width of a Full. Two Twin XL mattresses placed side by side also make up a Split King.
Split King is the size to know if you're considering an adjustable base. Because it's two separate Twin XL mattresses under one set of sheets, each person can raise or lower their own head and foot, choose their own firmness, and move without disturbing the other side. It's the most flexible setup for two people with different sleep preferences.
King vs. California King: what's the difference?
This is the most common point of confusion. A standard King is wider but shorter (76" x 80"); a California King is narrower but longer (72" x 84"). Choose a King if width and shoulder room matter most, or if your bedroom is closer to square. Choose a California King if you or your partner are tall and want the extra four inches of length, or if the room is long and narrow where a slimmer footprint fits better. Bedding is sized differently for each, so confirm the size before buying sheets.
How to choose the right size
Start with who sleeps in the bed, then check the room. A good rule is to leave at least two feet of walking space on each side and at the foot of the bed. Measure your room and your doorways and stairwells before you commit to a King or California King, since those can be tight to move into older homes. If two of you have different comfort preferences or one of you wants an adjustable base, Split King solves both at once.
Shopping mattresses at Retreat Home
We carry mattresses in every size above across the brands we trust, and our sleep team can help you match a size and feel to your room and your sleep style. Every mattress comes with our 120-night trial, so you have time to be sure it's right, and mattresses ship free. Browse the full range in our mattress collection, or visit our Hayward, Wisconsin showroom to lie down on a few before you decide.
Frequently asked questions
What are the standard mattress sizes?
The standard U.S. mattress sizes are Twin (38" x 75"), Twin XL (38" x 80"), Full (54" x 75"), Queen (60" x 80"), King (76" x 80"), and California King (72" x 84"). Split King, made of two Twin XL mattresses, is common for adjustable beds.
What is the most popular mattress size?
Queen (60" x 80") is the most popular size. It comfortably fits two people while taking up less room than a King, which suits most bedrooms.
What is the difference between a King and a California King?
A King is wider and shorter (76" x 80"); a California King is narrower and longer (72" x 84"). Choose a King for width, a California King for length.
What size mattress is best for an adjustable base?
Split King is best for a base two people share, because each side adjusts independently. Twin XL works for a single adjustable bed.
How much room do I need for a King bed?
Plan for a bedroom of about 12' x 12' or larger so there's room to walk around the bed and fit other furniture comfortably.