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How Big is a King Size Mattress?

King Mattress Dimensions

Sharing a small mattress with someone can come with big problems. While it is possible to share a full size or twin size mattress with a partner, it can become uncomfortable and lead to fights for the blanket, snoring, tossing and turning. You are quick to discover that you are struggling to fall asleep at night and you no longer wake up feeling well-rested. It is time to find better sleep for you and a partner, which means it is time for a larger, king size mattress.

All Mattress Dimensions

What is a king size mattress?

Although there are several variants, a standard king size mattress is 76 inches by 80 inches, measuring 16 inches wider than a queen size mattress. A standard king size also measures the same as two twin XL mattresses pushed together (also known as a split king). As you consider a traditional king size mattress versus a split king, consider who will be sleeping on the bed and how each sleeper’s sleep needs may differ. Split king mattresses are a great option for couples looking customize their sleep setup to meet two different sleep needs.

History of the king size bed

Until around the 1940s, Americans usually slept on twin or full size mattresses. It was not until the mattress industry introduced the king and queen size mattresses that larger mattresses became more popular. King and queen sizes started gaining popularity in the 1950s, due in part to younger generations of Americans growing taller than previous generations. By the 1960’s, the king and queen size mattress were even more popular. Oversized mattresses are still popular today thanks to the extra space they provide and the high quality sleep that comes with it.

King Size Mattress Variants

  • California King

A California king measures 72 inches by 84 inches, making it 4 inches narrower and 4 inches longer than a standard king size mattress. Being that it measures longer, the California king is a great option for taller sleepers or sleepers who share the foot of their bed with furry friends.

  • Texas King

The Texas king is much larger than both a king and a California king size mattress. At a sizeable 80 inches by 98 inches, it has plenty of room for tall sleepers to stretch out. However, its size means it will be too large for most bedrooms.

  • Alaskan King

An Alaskan king mattress is the largest mattress on the market and comes in at a whopping 108 inches by 108 inches, or 9 feet by 9 feet. Being so large, this mattress offers plenty of room for the whole family, but you will want to have an extra-large bedroom to accommodate it. The Alaskan king size mattress will require some additional research to find a bed frame and bed linens to fit. More often than not, an Alaskan king mattress is purchased through a custom or specialty dealer rather than a traditional mattress outlet.

King Mattress
Cal King Mattress
Texas King Mattress
Alaskan King Mattress
Dimensions
76" x 80"
72" x 84"
80" x 98"
108" x 108"
Surface Area
6,080 square inches
6,048 square inches
7,840 square
inches
11,664 square
inches
Room Size Needed
12' x 12'
or larger
13' x 15'
or larger
14' x 16'
or larger
14' x 16'
or larger
Great For
Couples or singles needing more space
Families or singles who need more foot room
Taller sleepers of families looking for more sleep space
Large families
looking for ample
sleep space
  • King Mattress

    Dimensions
    76" x 80"

    Surface Area
    6,080 square inches

    Room Size Needed
    12' x 12'
    or larger

    Great For
    Couples or singles
    needing more space

  • Cal King Mattress

    Dimensions
    72" x 84"

    Surface Area
    6,048 square inches

    Room Size Needed
    13' x 15'
    or larger

    Great For
    Families or singles who
    need more foot room

  • Texas King Mattress

    Dimensions
    80" x 98"

    Surface Area
    7,840 square inches

    Room Size Needed
    14' x 16'
    or larger

    Great For
    Taller sleepers or families
    looking for more sleep

  • Alaskan King Mattress

    Dimensions
    108" x 108"

    Surface Area
    11,664 square inches

    Room Size Needed
    14' x 16'
    or larger

    Great For
    Large families looking
    for ample sleep space







Room requirements for a king size mattress

A king size mattress takes up a lot of space, so it is important to make sure you have enough room for an oversized mattress before you order. A good rule of thumb is to make sure that you have two feet of space on both sides and at the foot of the bed to leave room for any bedroom accessories and making the bed. Be sure to include the size of your bedframe, headboard, and footboard when considering measurements for a king size bed, too.

Does BedInABox® sell a king size mattress?

Yes! All of our mattresses are available in a king size. We have six different mattress models that are designed to meet different sleep needs and preferences. For sleepers who want a split king for an adjustable bed frame, we offer five of our mattresses in twin xl sizes to pair with our MotionInABox™ adjustable base. We also offer five of our mattresses in California king sizes, so that taller sleepers have plenty of options, too!

BedInABox® is here to solve your sleep problems, including those that stem from sharing a small mattress. An oversized mattress, such as a king size or California king, is often a simple solution for your sleep woes. So if you or partner have trouble sleeping because you are sharing a smaller bed, it may be time to consider a mattress upgrade. Our newly introduced Starter Bundle, which includes 1 BedInABox® mattress of your choice and 1 Clever Connect™ foundation, can save you up to $893 and gives you everything you need to start getting better sleep.