Mattress Sizes Chart and Dimensions Guide
Buying a bed starts with one question: what size do you actually need? This guide gives you every standard US mattress size with exact dimensions in inches, feet and centimeters, a to-scale comparison diagram, and simple advice on matching a size to your room and the way you sleep. No guesswork — just the numbers.
Short answer: Standard US mattress sizes run from a Mini Crib at 24″ × 38″ up to a California King at 72″ × 84″. The sizes most homes buy are the Twin (38″ × 75″), Full (54″ × 75″), Queen (60″ × 80″) and King (76″ × 80″) — the full mattress sizes chart below gives every size in inches, feet and centimeters, with the room each one needs.
Contents
- Mattress Sizes Chart
- Less Common Mattress Sizes
- How Thick Is a Mattress?
- Mattress Sizes Compared to Scale
- How to Choose the Right Mattress Size
- Popular Size Guides
- Mattress Sizes in CM and Feet
- Frequently Asked Questions
Mattress Sizes Chart (All Standard US Sizes)
| Mattress Size | Inches (W × L) | Centimeters | Feet | Best For |
|---|---|---|---|---|
| Mini Crib | 24″ × 38″ | 61 × 97 cm | 2.0 × 3.2 ft | Mini cribs, bassinets |
| Crib | 28″ × 52″ | 71 × 132 cm | 2.3 × 4.3 ft | Babies and toddlers |
| Twin | 38″ × 75″ | 97 × 191 cm | 3.2 × 6.3 ft | Kids, teens, small rooms |
| Twin XL | 38″ × 80″ | 97 × 203 cm | 3.2 × 6.7 ft | Tall teens, dorm rooms |
| Full (Double) | 54″ × 75″ | 137 × 191 cm | 4.5 × 6.3 ft | Single adults, guest rooms |
| Queen | 60″ × 80″ | 152 × 203 cm | 5.0 × 6.7 ft | Couples, master bedrooms |
| King | 76″ × 80″ | 193 × 203 cm | 6.3 × 6.7 ft | Couples who want space |
| California King | 72″ × 84″ | 183 × 213 cm | 6.0 × 7.0 ft | Tall sleepers (over 6 ft) |
| RV Queen Short | 60″ × 75″ | 152 × 191 cm | 5.0 × 6.3 ft | RVs and campers |
Tip: mattress thickness (height) is separate from these dimensions — most mattresses are 8″ to 14″ thick. Always measure your bed frame’s inside dimensions before ordering, and allow about half an inch of clearance on each side.
Less Common Mattress Sizes
Beyond the nine standard sizes, a handful of specialty sizes show up in specific situations — adjustable beds, larger bedrooms and RVs. They are worth knowing about before you order, because bedding for them is sold separately and is not interchangeable with standard sizes.
| Size | Inches (W × L) | What It Is |
|---|---|---|
| Split King | 76″ × 80″ (two 38″ × 80″ halves) | Two Twin XL mattresses on one King frame, usually with an adjustable base |
| Split Queen | 60″ × 80″ (two 30″ × 80″ halves) | A Queen split into two halves for adjustable bases |
| Olympic Queen | 66″ × 80″ | A wider Queen, found in some larger RVs and older stock |
| California Queen | 60″ × 84″ | Queen width with California King length, for tall single sleepers |
| Split California King | 72″ × 84″ (two 36″ × 84″ halves) | Two half-width Cal King mattresses on one frame |
| Texas King | 80″ × 98″ | An oversized King, wider and longer than a standard King, made for very large bedrooms |
| Wyoming King | 84″ × 84″ | A square oversized King, as wide as it is long, made for very large bedrooms |
| Alaskan King | 108″ × 108″ | The largest oversized mattress, a 9-foot square bed made for very large bedrooms |
A note on real-world sizing: manufacturers are allowed small tolerances, so a finished mattress can measure up to about half an inch smaller than its labeled size, and brands round their published figures differently. A half-inch difference is normal and harmless — but if your frame is an antique or a tight fit, measure the mattress itself rather than trusting the label.
How Thick Is a Mattress? (Height Is Not Standardized)
Width and length are standard; thickness is not. Most mattresses sold today are between 8″ and 14″ thick: slim foam and bunk models start around 6″–8″, mainstream hybrid and innerspring models sit at 10″–12″, and pillow-top designs reach 14″ or more. Thickness matters for two practical reasons. First, your fitted sheets must have a pocket depth that matches — a standard pocket fits up to about 12″, while thicker mattresses need deep-pocket sheets. Second, total bed height affects how easily you get in and out: the top of the finished bed (frame + foundation + mattress) ideally lands near knee height, roughly 24″–25″ for most adults. On bunk beds and trundles, always check the maker’s maximum mattress thickness, because the guard rail must still rise above the sleeping surface.
Our standard dimensions match the figures published in the Sleep Foundation’s mattress sizes guide, which also notes that thickness varies by model because it is not part of the size standard.
Mattress Sizes Compared to Scale
Charts of numbers only tell half the story. This diagram draws the six most popular sizes to the same scale, so you can see exactly how much floor and sleeping space each one takes up.
The jump from Queen to King is among the biggest in the chart — a full 16 inches: a King gives two sleepers the same personal width as two Twin XL beds pushed together — 38 inches each. The California King trades 4 inches of that width for 4 extra inches of length, which is why tall sleepers prefer it.
How to Choose the Right Mattress Size
1. Measure your room first
Leave at least 24–30 inches of walking space around the sides and foot of the bed. As a rule of thumb, a Queen needs a room of at least 10 × 10 ft, and a King needs at least 12 × 10 ft (12 × 12 ft is more comfortable).
To work out whether a size truly fits, do the full calculation: take the room’s width, subtract the bed frame’s outside width (frames typically add 2–5 inches beyond the mattress), then divide what is left by two — that is your walkway on each side. Aim for at least 24 inches, and 30–36 inches where a door swings or drawers open into the space. A Queen in a 10 ft (120″) room, for example, leaves about 27–29 inches per side once the frame is counted — comfortable. The same room with a King leaves under 20 inches, which is why we set 12 × 10 ft as the King’s practical minimum.
Traveling instead of furnishing a room? Camper and motorhome beds follow different measurements entirely — see our guide to RV and camper mattress sizes before you buy.
For camper and motorhome beds, compare your measurements against the Sleep Foundation’s RV mattress sizes chart, since RV sizes deliberately depart from home sizes to save space.
2. Count the sleepers — and their height
Anyone over 6 feet tall should look at an 80-inch or longer mattress (Twin XL, Queen, King or California King). A standard 75-inch Twin or Full will leave tall sleepers with their feet at the very edge.
3. Think about the next five years
Kids outgrow Twin beds, and couples rarely go back to a smaller size. If the room and budget allow it, sizing up now is cheaper than replacing a bed in two years.
Still torn between two sizes? Work through the three questions in our mattress size finder guide and it will narrow the chart down to a single recommendation.
Popular Size Guides
King Size Bed Dimensions — a King is 76″ × 80″. See the full guide with frame dimensions, room sizes and King vs California King.
Queen Size Mattress Dimensions — a Queen is 60″ × 80″, the most popular size in the US. Full dimensions, room fit and Queen vs Full explained.
For a nursery, start smaller: our crib mattress size guide explains the one mattress size that is fixed by federal safety rules rather than by convention.
Twin Size Mattress Dimensions — a Twin is 38″ × 75″, the standard kids’ and bunk-bed size. See also the Twin XL for taller sleepers.
Full vs Queen and Queen vs King — the two comparisons most shoppers need, with dimensions, room sizes and honest advice. Not sure where to start? Try the Mattress Size Guide finder.
Sheet Sizes — flat and fitted dimensions for every bed
Bed Frame Sizes — how much bigger a frame is than its mattress
Mattress Sizes in CM and Feet
Shopping on a site that lists sizes in centimeters? The conversions are simple: multiply inches by 2.54. The most searched ones: a Queen is 152 × 203 cm (5 × 6.7 ft), a King is 193 × 203 cm (6.3 × 6.7 ft) and a Twin is 97 × 191 cm (3.2 × 6.3 ft). The chart at the top of this page lists every size in all three units.
If your shortlist is down to two sizes, the head-to-head pages settle the details: Full vs Queen for guest rooms and first apartments, and Queen vs King when the master bedroom is on the line.
Frequently Asked Questions
What is the biggest mattress size?
The Alaskan King is the biggest mattress size at 108″ × 108″. The California King is the largest of the standard sizes at 72″ × 84″, while the King is the widest standard size at 76″ × 80″. By total surface area among standard sizes, the King is slightly bigger than the California King (6,080 vs 6,048 square inches).
What mattress size do most couples use?
The Queen (60″ × 80″) is the most popular choice for couples in the US because it fits standard bedrooms. Couples who want maximum personal space choose a King.
Is a Full bed the same as a Double?
Yes. “Full” and “Double” are two names for the same 54″ × 75″ size.
What size is a single bed?
A single bed usually means a Twin (38″ × 75″). In dorms and for tall teens, the Twin XL (38″ × 80″) is the common single size.
How much bigger is a King than a Queen?
A King is 16 inches wider than a Queen and the same length — about 27% more sleeping surface.
Do mattress sizes differ by country?
Yes. UK and EU sizes use different names and dimensions (for example, a UK King is 60″ × 78″). This chart uses standard US sizes.
Sources: Sleep Foundation — Mattress Sizes guide; Sleep Foundation — RV Mattress Sizes.