Both are 75 in long, but a Full (54 in wide) is 16 in wider than a Twin (38 in). Both are single-sleeper sizes: a Twin for a child or a tight space, a Full for one adult with room to spread out.
Twin: best for children, bunk beds, and rooms that hold two beds.
Full (Double): best for a single adult, a teen, or a guest room.
Both stop at 75 inches, so tall sleepers should look at a Twin XL or Queen.
A Full and a Twin are the same length, but a Full is much wider. A Twin measures 38 inches wide by 75 inches long. A Full, also called a Double, measures 54 inches wide by 75 inches long, 16 inches wider with the same 75-inch length. That extra width gives a Full 4,050 square inches of surface against a Twin's 2,850. Both are single-sleeper sizes at heart: a Twin fits a child, or a tight space, and a Full gives one adult room to spread out.
Feature | Twin | Full (Double) |
Width | 38 inches | 54 inches |
Length | 75 inches | 75 inches |
Total surface area | 2,850 sq in | 4,050 sq in |
Best for | Children, single sleepers, bunk beds, small rooms | Solo adults, guest rooms, teens |
Minimum room size | About 7 x 10 feet | About 10 x 10 feet |
Also known as | Single | Double |
Twin size, in brief
A Twin is the smallest standard mattress, 38 by 75 inches. It is the default for children's rooms, bunk beds, and tight spaces, and two can fit in a shared kids' room where a larger bed would not. At 75 inches long, it can be short for a tall teenager or adult, who may be better served by a Twin XL.
Full size, in brief
A Full is 16 inches wider than a Twin at the same length. That width makes it comfortable for a single adult who likes room to move, and workable for a guest room. It is a common step up from a Twin for a growing child who has outgrown a smaller bed but does not yet need a Queen.
Which one should you choose?
For a young child or for a room that has to hold two beds, a Twin is the practical choice. For a single adult, a teen, or a guest room, a Full gives noticeably more room without taking much more floor space. If the sleeper is tall, note that both stop at 75 inches; a Twin XL or Queen adds the length they will want.
Twin and Full at Avocado
Avocado offers both Twin and Full across its line of certified organic mattresses, built with the same materials and support system. Whichever size fits the room, what is inside the mattress is the same.
Frequently asked questions
Is a Full much bigger than a Twin?
In width, yes. A Full is 16 inches wider, 54 inches against 38 inches. Both are 75 inches long, so a Full offers more room to spread out but no more length.
Is a Full the same length as a Twin?
Yes. Both are 75 inches long. The difference between them is entirely in width.
Can two people sleep on a Full?
One adult very comfortably; two adults only tightly. A Full works better as a roomy single bed than as a shared one.
Is a Twin or Full better for a child?
A Twin is the usual choice for younger children and bunk beds. A Full suits an older child or teen who wants more room.
Is a Full the same as a Double?
Yes. Full and Double are the same size: 54 by 75 inches.
Can I use Twin sheets on a Full?
No. The two sizes are different widths, and the sheets are not interchangeable.
Related size guides