Buying Guide · Updated 2026-10-24
Mattress Sizes and Dimensions Chart
The six standard US 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"). A queen is the smallest bed we suggest for two adults.
Mattress Size Chart
Sizes are the nominal US dimensions brands sell under. "Width per sleeper" is half the bed, for two people sharing.
| Size | Inches | Centimeters | Surface area | Width per sleeper | Best for |
|---|---|---|---|---|---|
| Twin | 38" x 75" | 97 x 191 cm | 2,850 sq in | — | One child or a small adult; bunk beds |
| Twin XL | 38" x 80" | 97 x 203 cm | 3,040 sq in | — | One adult, including tall adults; dorm rooms |
| Full (Double) | 54" x 75" | 137 x 191 cm | 4,050 sq in | — | One adult who wants room to spread out |
| Queen | 60" x 80" | 152 x 203 cm | 4,800 sq in | 30" | Most couples; the smallest bed we suggest for two |
| King | 76" x 80" | 193 x 203 cm | 6,080 sq in | 38" | Couples who want space, or who share with a child or pet |
| California King | 72" x 84" | 183 x 213 cm | 6,048 sq in | 36" | Tall sleepers; long, narrow bedrooms |
The six sizes drawn to scale
King vs California King
A California king is not the bigger bed. It is 4 inches longer and 4 inches narrower than a king, so it has 32 fewer square inches of surface.
| King | California King | |
|---|---|---|
| Size | 76" x 80" | 72" x 84" |
| Centimeters | 193 x 203 cm | 183 x 213 cm |
| Surface area | 6,080 sq in | 6,048 sq in |
| Width per sleeper (2 people) | 38" | 36" |
| Room (30" walkway) | 11' 4" x 9' 2" | 11' x 9' 6" |
| Fits a sleeper up to about | 6' 2" | 6' 6" |
| Best for | Couples who want space, or who share with a child or pet | Tall sleepers; long, narrow bedrooms |
Choose a king if
- You share the bed and want the most width (38" each, the same as a Twin XL).
- A child or pet often joins you.
- You want the widest choice of sheets, frames and models.
Choose a California king if
- You or your partner are over about 6' 2". A pillow uses the top few inches of an 80" bed.
- Your room is long but narrow. The Cal King needs 4" less wall width.
- Your feet hang off the end on a standard king.
Sheets do not swap between the two. A king fitted sheet is too short for a California king, and a California king sheet is too narrow for a king.
King vs Queen
Both are 80 inches long. A king is 16 inches wider. For a couple, that is 38 inches each instead of 30.
| Queen | King | |
|---|---|---|
| Size | 60" x 80" | 76" x 80" |
| Centimeters | 152 x 203 cm | 193 x 203 cm |
| Surface area | 4,800 sq in | 6,080 sq in |
| Width per sleeper (2 people) | 30" | 38" |
| Room (30" walkway) | 10' x 9' 2" | 11' 4" x 9' 2" |
A queen fits most couples and most bedrooms. Move up to a king if either of you moves a lot at night, if you sleep hot and want distance, or if your room is at least about 11' 4" wide on the headboard wall. Couples who wake each other up should also compare motion isolation; see our best mattress for couples picks.
Full vs Queen
A full (also called a double) is 54" wide. Two adults get 27 inches each. That is less than a standard crib mattress, which is about 28 inches wide.
A queen adds 6 inches of width and 5 inches of length. For two adults, treat it as the minimum.
Twin vs Twin XL
Same width (38"). A Twin XL is 5 inches longer, at 80". That is the same length as a queen or a king.
For a single adult, a Twin XL gives full-length legroom in the smallest footprint. A twin is fine for children and for bunk beds.
What Is a Split King?
A split king is two Twin XL mattresses (38" x 80" each) side by side. Together they make a 76" x 80" king.
- Each sleeper can pick a different firmness.
- Each side can sit on its own adjustable base, so one person can raise their head while the other lies flat.
- Each half is a separate mattress, so you can replace one half without replacing both.
- There is a seam down the middle. Two people who like to cuddle will feel it.
- Sheets: two Twin XL fitted sheets, one king flat sheet.
A split California king works the same way: two 36" x 84" halves.
Specialty and Oversized Mattress Sizes
These exist, but few brands make them. Expect fewer models, custom sheets, and longer delivery times.
| Size | Inches | Centimeters | Notes |
|---|---|---|---|
| Full XL | 54" x 80" | 137 x 203 cm | A full with Twin XL length. Hard to find sheets for. |
| Olympic Queen | 66" x 80" | 168 x 203 cm | Six inches wider than a queen. Few brands make it. |
| Split King | 76" x 80" | 193 x 203 cm | Two Twin XL mattresses (38" x 80" each) side by side. |
| Split California King | 72" x 84" | 183 x 213 cm | Two 36" x 84" halves. Mostly sold with adjustable bases. |
| Wyoming King | 84" x 84" | 213 x 213 cm | A square bed. Custom sheets. |
| Texas King | 80" x 98" | 203 x 249 cm | Extra long for very tall sleepers. Custom sheets. |
| Alaskan King | 108" x 108" | 274 x 274 cm | A 9-foot square for family co-sleeping. Check doorways first. |
| RV / Short Queen | 60" x 75" | 152 x 191 cm | Queen width, 5 inches shorter, to fit camper beds. |
| Crib | 28" x 52" | 71 x 132 cm | About 28" x 52". A standard crib mattress also fits most toddler beds. |
What Room Size Do You Need?
Our math: the headboard sits against one wall, with a walkway on both sides and at the foot. Pick 30 inches for a tight fit or 36 inches for comfort. Nightstands and dressers need more.
Minimum room
10' x 9' 2"
10' along the headboard wall (60" + 2 x 30"), 9' 2" deep (80" + 30").
Bigger Beds Need More Support
Size changes how a mattress wears. A queen or king spans a wide frame, and the middle is where it sags first if the frame flexes.
- Check the warranty's frame rules before you buy a queen or larger. Beautyrest's warranty, for example, says a queen or king frame without a metal center support needs at least 5 hardwood or metal slats with legs on the 3 center slats, and that an inadequate foundation can void the warranty. See our Beautyrest Black review and whether you need a box spring.
- Two sleepers usually leave two body impressions. Rotating the mattress head to foot spreads the wear. See how often to rotate a mattress.
- Know the sag limit before you need it. Most warranties only cover body impressions past a set depth, often 1.5 inches. Our 1.5-inch sag threshold explainer shows how to measure it.
Still choosing a model? Start with our how to choose a mattress guide.
Mattress Size FAQ
What are the standard mattress sizes?
The six standard US mattress sizes are Twin (38" x 75"), Twin XL (38" x 80"), Full or Double (54" x 75"), Queen (60" x 80"), King (76" x 80") and California King (72" x 84"). Real mattresses can measure up to about half an inch smaller.
Is a California king bigger than a king?
No. A California king is 4 inches longer but 4 inches narrower than a king. A king has 6,080 square inches of surface; a California king has 6,048. Pick a California king only if you are tall or your room is long and narrow.
What size is a split king?
A split king is two Twin XL mattresses (38" x 80" each) side by side. Together they are 76" x 80", the same as a king. It lets each sleeper choose a different firmness or raise their side on an adjustable base.
Are a full and a double bed the same size?
Yes. Full and double are two names for the same 54" x 75" mattress. Two adults get only 27 inches each, so most couples are better on a queen.
How big a room do I need for a king bed?
With a 30-inch walkway on both sides and at the foot, a king (76" x 80") needs a room about 11' 4" wide on the headboard wall and 9' 2" deep. With a 36-inch walkway, plan on about 12' 4" by 9' 8". Add more width for nightstands.
Is a Twin XL the same length as a queen?
Yes. A Twin XL, a queen and a king are all 80 inches long. A Twin XL is the cheapest way for a tall single adult to get full-length legroom.
Sources
Updated · By SleepUnpacked Research Team
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