Best online mattress size guide

Olympic Queen or Texas King: How to Pick the Right Mattress Size

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Buying the best online mattress won’t help you much if you choose the wrong size. Many people tend to underestimate how much personal space they need to sleep comfortably.

Couples are especially prone to buying too-small mattresses. You never realize just how cramped the bed was until you ditch your double mattress for a king size.

The best mattress size will depend on your situation and preferences. Obviously, the more you are in the bed the bigger the mattress needs to be. A larger mattress will also be more comfortable if you prefer sprawling out on your bed as you sleep.

Here’s a simple test for couples to determine whether a mattress is big enough. Lie on your back on the mattress and put your hands under your head. If your elbows are too close or are touching, the mattress is too small. If there is a good distance between your elbows, it has plenty of space for both of you.

It also goes without saying that the mattress needs to be a match, size-wise, to your bed. But if you want a smaller or bigger mattress than your bed, you can always buy a new matching box spring or foundation. In fact, most online mattress companies sell a variety of frames alongside their mattresses.

Mattress Size Chart

Mattress sizes can be split into two general groups: standard sizes and specialty sizes. Here are the common dimensions for each size.

Note: Exact dimensions may slightly vary by an inch or two among different brands.

Standard Sizes

Crib mattress 27” x 52”
Twin size 38” x 75”
Full (double) size 54” x 75”
Queen size 60” x 80”
King size 76” x 80”

Specialty Sizes

Small single mattress 30” x 75”
Twin XL 38” x 80”
Small double 48” x 75”
Double XL 54” x 80”
Olympic queen 66” x 80”
California king 72” x 84”
Grand king/Texas king 80” x 98″

Of course most mattress brands are not available in all these sizes. Some like the Texas king size are not very common. The most common ones you’ll find online and in stores are twin, twin XL, full, queen, king and California king.

Choosing the Right Mattress Size

Choosing the best online mattress size

Crib/Toddler mattress

This is the first mattress you buy for your toddler. This size is usually okay until around 2 years of age when you’ll need to move up to a twin size.

Remember to check that the crib mattress is firm enough. It shouldn’t be too soft nor should it have a pillow top. The extra softness can be dangerous to babies.

Twin size

A twin size mattress is perfect for kids who are just about growing past their cribs. Kids can sleep on it until they are much older.

Twin sizes are also great for a guest bed, on a daybed or for a small room. But note that the mattress may not be long enough for some adults. For adults, you should probably consider a twin XL.

Twin XL

A twin XL is just as wide as a twin size but 5 or 6 inches longer. This provides more feet space for taller adults or children.


A full or double size mattress is 15 to 16 inches wider than a twin size mattress. It’s best for a single adult. But note that it’s just as long as a twin. So if you are tall, get the specialty double XL mattress.

You should also consider getting a full size mattress for your child instead of a twin or twin XL. It not only ensures they’ll not outgrow it, it also provides enough space for them to sit up or sprawl around. It also comes in handy during sleepovers with friends. Two kids can fit in it without any problem.


This is the standard size for couples. It’s wide enough such that everyone has enough personal space and long enough for taller adults.

For couples who find the standard queen too small but don’t want to get a King size, consider the specialty Olympic queen size.


A king size bed gives each person roughly a twin-size bed of personal space. This is plenty enough to spread your arms and roll without disturbing the other person.

You also get plenty of length to stretch your feet.

Before buying a King size mattress, make sure it will fit through doorways and corridors. Also check that there will be enough space for it in the bedroom.

California King

A California king is best for longer bedrooms. It’s 4 inches narrower than a standard King but 4 inches longer.

Custom and Split Sizes

If you are planning to buy a queen or larger mattress but you are not sure it will fit the doorway or corridor, buy a split mattress.

Some companies offer a split option where the mattress comes in two halves that can easily be joined together again. A split mattress is also ideal if you and your partner have different comfort needs.

Some companies also offer custom sizes. These are great for situations where standard sizes won’t do such as boats or in an RV.

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