Mattress Size Calculator
Tell the calculator how many people sleep in the bed and how tall they are. It matches you to a standard mattress size and shows the room you have left around it.
| Size | Width (in) | Length (in) | Best for |
|---|---|---|---|
| Twin | 38 | 75 | One sleeper, kids rooms, bunk beds |
| Twin XL | 38 | 80 | One taller sleeper, dorms, adjustable bases |
| Full | 54 | 75 | One adult who wants room, small guest rooms |
| Queen | 60 | 80 | Two sleepers, the most common choice |
| King | 76 | 80 | Two sleepers who want space, larger rooms |
| Cal King | 72 | 84 | Tall sleepers who need extra length |
How the calculator picks a size
It gives each sleeper 30 in of width and adds the length you need for your height, then matches that to the closest standard size. A single sleeper usually lands on a twin or twin xl, two sleepers on a queen, and taller couples on a king or cal king. Sharing a bed is the fastest reason to move up a size.
Reading the clearance numbers
The tool subtracts the bed from your room and splits the leftover space between the two sides. Under 24 in per side makes it hard to make the bed and walk past it. Measure at the narrowest point and leave room for nightstands, dresser drawers, and closet doors.
When to size up or down
If you are between two sizes, go up when you share the bed or the sleeper is tall, and down when the room is small. A bed you can walk around beats an extra few inches of mattress. A cal king trades width for length, so pick it only when height is the bigger problem.
Our picks
Questions about this calculator
What size mattress should I buy for two people?
At 30 in of width per person, two sleepers want at least 60 in, which is a queen. A king adds 16 more inches of width if your room can spare it. A full is only 54 in wide, so it feels tight for two adults who move in the night.
What is the difference between a queen and a king?
A queen measures 60 by 80 in and a king measures 76 by 80 in. The king is 16 in wider at the same length. A cal king is 72 by 84 in, so it gives up 4 in of width for 4 more inches of length.
How much space should I leave around a bed?
Aim for at least 24 in on each side of the mattress. That is enough to make the bed, open a drawer, and walk past without turning sideways. If the room is tight, keep the larger gap on the side you use to get in and out.
Is a full size bed big enough for two people?
A full is 54 by 75 in, which is under the 60 in that two sleepers usually need. It can work for two smaller adults or a guest room, but most couples are more comfortable on a queen. Height matters too, since a full stops at 75 in.
What is a Twin XL and who needs one?
A twin xl is 38 by 80 in, the same width as a twin but 5 in longer. It fits one taller sleeper, a dorm room, or a split adjustable base. Two twin xl beds side by side equal the width of a king.
Does the bed frame need to match the mattress size?
Yes. Buy the frame for the mattress size you choose, since a queen mattress will not sit on a twin frame. A cal king needs its own frame because it is narrower and longer than a standard king.
How do I measure a room for a bed?
Measure wall to wall in both directions and note the shortest distance in each. Subtract the bed dimensions and split the leftover space between the two sides. Remember to account for a headboard and any furniture that opens into the walking space.