A Simple Guide to Mattress Sizes and Bed Dimensions

Mattress shopping isn’t just about finding a mattress cozy enough to lull you to sleep at night. Before you can even consider feel, you have to ask yourself an important question: how big should your mattress be?

When selecting a mattress size, there are a couple factors to consider. First, how much space do you need? And second, how much space do you have? If you’re sharing your bed with someone else—or if you’re the kind of person who likes to sprawl out when you sleep—you may want a larger mattress. But if space is limited in your bedroom, it might be worth downsizing a bit.

To help you understand all your options, we’ve created a guide to the six standard mattress sizes. And in addition to walking you through exactly how big each mattress size is, we’ll try to help you understand which mattress size is right for you.

Twin Mattress

Twin Bed Dimensions: 38 inches by 75 inches
Great for: Kids, small single sleepers, small spaces
Recommended Room Size: 7 feet by 9–10 feet

The smallest standard-size mattresses around, twin mattresses are great for saving space. At 38 inches wide and 75 inches long, a twin mattress won’t demand too much bedroom real estate—making it a great pick for a tight or narrow room.

Experts estimate that your room only needs to be 7 feet wide and 9–10 feet long to comfortably house a twin bed. That said, you may want your room to be a little bigger to comfortably house a twin bed and other furniture.

One thing to note: since twin mattresses are only 75 inches long, they may be too short for taller teens and adults. This makes them a suitable choice for many children, as well as for shorter teens and adults. But taller teens and adults may want to size up to sleep comfortably. 

Twin XL Mattress

Twin XL Bed Dimensions: 38 inches by 80 inches
Great for: Teenagers, tall single sleepers, small spaces
Recommended Room Size: 7–8 feet by 10 feet

Twin XL mattresses are a lot like twin mattresses. They’re just 5 inches longer. And while that extra length may not sound like a lot, it could mean the difference between your feet hanging off the bed and your feet fitting on the bed.

Still, twin XL mattresses don’t demand too much space. According to experts, you should be able to fit a twin XL bed in a room that’s at least 7–8 feet wide and at least 10 feet long.

These features make twin XL mattresses great for tall single sleepers in tight spaces. (Given this, it should come as no surprise that twin XL mattresses are a popular pick for dorm rooms.)

Full Mattress

Full Bed Dimensions: 54 inches by 75 inches
Great for: Single sleepers, couples (who don’t need much space), guest bedrooms
Recommended Room Size: 9–10 feet by 10 feet

Full mattresses are a classic option for single sleepers who want a little more space—or couples who don’t mind snuggling close together. At 54 inches wide, a full mattress is 16 inches wider than a twin mattress. But at 75 inches long, it’s exactly as long as a twin mattress. (This means a full mattress is actually shorter than a twin XL mattress.)

Since full mattresses are wider than twin mattresses, they demand a little more space. Experts recommend making sure your room is at least 9–10 feet wide and 10 feet long to comfortably house a full bed.

Though full mattresses are a popular pick for young adults, it’s worth noting that their length is somewhat limiting. If you’re too tall for a twin mattress, you’re also too tall for a full mattress. (They are, after all, the same length.) So you might want to size up, if you have the space to.

Queen Mattress

Queen Bed Dimensions: 60 inches by 80 inches
Great for: Single sleepers (who like space), couples
Recommended Room Size: 10 feet by 10–11 feet

If you’re sharing a bed with a partner—or if you’re simply craving more space—a queen mattress can be a great option. At 60 inches wide and 80 inches long, a queen mattress is considerably wider than a twin or full mattress. It’s also 5 inches longer than a twin or full mattress, and exactly as long as a king mattress.

Given their size, queen mattresses need a fair amount of space. According to experts, you’ll want a room that’s at least 10 feet wide and 10–11 feet long to house a standard queen bed.

Since queen beds are pretty roomy, they can be a luxurious choice for single sleepers and a comfortable choice for couples. But since they’re not terribly large, they can still conveniently fit inside many smaller bedrooms.

King Mattress

King Bed Dimensions: 76 inches by 80 inches
Great for: Single sleepers (who like lots of space), couples (who like lots of space)
Recommended Room Size: 12 feet by 12 feet

If a queen mattress simply isn’t big enough for you, consider snagging a king mattress, instead. At 76 inches wide, a king mattress is a whopping 16 inches wider than a queen mattress. (It’s worth noting, though, that the two are the same length.)

All that added width needs somewhere to go, so king beds demand a lot of bedroom real estate. Experts recommend a room that’s at least 12 feet wide and 12 feet long for a standard king bed. (That means you need a room that’s about 34–44 square feet bigger than what you’d need to house a queen bed.)

But if you want a lot of sleeping space—and you have a lot of bedroom space to spare—a king mattress can be an excellent choice. 

California King Mattress

California King Bed Dimensions: 72 inches by 84 inches
Great for: Tall single sleepers (who like lots of space), couples (who like space), tall couples
Recommended Room Size: 12 feet by 12 feet

California king mattresses may have a reputation for being the biggest mattresses around. But they’re technically smaller than standard king mattresses. At 84 inches long, a California king mattress is 4 inches longer than a king mattress. But at 72 inches wide, a California king mattress is 4 inches narrower than a king mattress. These dimensions make California king mattresses the longest mattresses around, though standard king mattresses are actually the widest.

Since California king beds are so large, they work best in bigger spaces. According to experts, California king beds fit most comfortably in rooms that are at least 12 feet wide and 12 feet long.

If you’re considering a California king mattress, you probably want a fair amount of sleeping space. So the biggest question is whether your priority is length or width. If you want space to sprawl out sideways, you might be better off with a king. But if length is what you’re after, a California king mattress is sure to deliver.