Last updated: July 2026
The six standard US mattress sizes are Twin (38×75 in), Twin XL (38×80), Full (54×75), Queen (60×80), King (76×80), and California King (72×84). Queen is the most popular for adults and needs about a 10×10-foot room; King needs closer to 12×12. This guide covers every size, the room each one fits, and the headboard, nightstand, and clearance measurements that finish the layout.
To check your own room in seconds, use the Bed Size Calculator.
US Mattress Size Chart
| Size | Width × Length (in) | Best for |
|---|---|---|
| Twin | 38 × 75 | Kids, single sleepers, bunk beds |
| Full (Double) | 54 × 75 | One adult, tight guest rooms |
| Queen | 60 × 80 | Couples, most adults |
| King | 76 × 80 | Couples wanting maximum width |
That is the quick reference. For every size in inches, cm and feet — plus mattress depth and sheet sizes — see the full mattress size chart.
What Room Size Each Bed Needs
A bed needs walkway clearance around the sides you use — about 30 inches to feel comfortable, 24 inches at a minimum. Add that to the mattress footprint and you get the room size. A Queen wants roughly 10×10 feet; a King is happiest at 12×12. Check your exact room with the Bed Size Calculator, or see the worked best bed size for a 10x10 room.
| Bed size | Minimum room | Comfortable room |
|---|---|---|
| Twin | 7 × 9 ft | 8 × 10 ft |
| Full | 9 × 9 ft | 10 × 10 ft |
| Queen | 9 × 9.5 ft | 10 × 10 ft |
| King / Cal King | 10 × 9.5 ft | 12 × 12 ft |
Nightstands, Headboards and Bed Height
A nightstand should sit roughly level with the top of the mattress — about 24 to 28 inches tall — and adds 18 to 24 inches to the bed's width on each side you place one. A headboard is the same width as the mattress or a few inches wider. Total bed height (floor to top of mattress) usually lands between 20 and 25 inches, which is a comfortable height to sit on and get out of.
All Bed & Mattress Guides
- Bed Size Calculator — What Fits My Room
- Mattress Size Chart: Every US Size
- Best Bed Size for a 10x10 Room
- Best Bed Size for a 10x12 Room
- King and California King Sizes
- Nightstand Height and Clearance
Frequently Asked Questions
There are six standard US sizes: Twin (38 by 75 inches), Twin XL (38 by 80), Full or Double (54 by 75), Queen (60 by 80), King (76 by 80), and California King (72 by 84). Queen is the most popular size for adults, and King is the widest.
A standard King is wider but shorter — 76 by 80 inches — while a California King is narrower but longer at 72 by 84 inches. The King suits couples who want maximum shared width; the California King suits taller sleepers or narrower, longer rooms.
A nightstand should sit roughly level with the top of your mattress, which usually means 24 to 28 inches tall. That keeps a lamp, phone, or glass of water within easy reach without towering over the bed. Measure your finished bed height and match it.
A Queen (60 by 80 inches) is the most popular choice for couples and fits most main bedrooms. If both partners want more personal space and the room is at least 12 by 12 feet, a King adds 16 inches of shared width. A Full is generally too narrow for two adults to sleep comfortably long-term.
Note: Sizes shown are standard US mattress dimensions; actual mattresses vary by an inch or two between brands, and depth ranges widely. Always measure your specific mattress and room before buying furniture.