King Size Bed Dimensions: Everything You Need to Know About King Size Mattresses

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/ May 10, 2021
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Feeling cramped in your bed alongside a partner, kids, and pets? Moving to a bigger bedroom? It might be time to upgrade to a king size bed.

A king size bed has plenty of positives going for it: It’ll provide more-than-generous space to you and a partner. It’s ideal for restless and light sleepers since there’s not as much of a chance of disturbing or being disturbed by a partner. And it certainly adds presence to a large bedroom, acting as an anchor amid the rest of the décor.

family lying in king size bed

But how big exactly is a king size mattress, and will it work in your bedroom?

Here, we’ve put together everything you need to know about king bed dimensions, the pros and cons of choosing this mattress size, and how to tell if it’s right for you.

We’re also explaining how king size bed dimensions compare to other mattress sizes and answering the most commonly asked questions about king size mattresses.

King size bed dimensions

A king size bed is the largest type of mattress on the market today. A standard king size bed measures 76 inches wide by 80 inches long.

In addition to the standard king size, there are also two common specialty king sizes. A split king has the same dimensions as a standard king but is formed from two 38 x 80-inch twin XLs placed side by side, and a California king mattress is slightly narrower and longer than a standard king, measuring 72 x 84 inches.

Then there are less widely available king sizes that include the Texas king, the Alaskan king, and the Wyoming king.

Below, you’ll find a chart that shows standard king bed dimensions in the most common units of measurement.

King Size Mattress Dimensions

Inches

76 x 80 in

Feet

6.33 x 6.67 ft

Centimeters

193 x 203.5 cm

Meters

1.93 x 2.035 m

Benefits of a king size mattress

If you’re thinking through king mattress dimensions to determine whether this size is a viable option, be sure to weigh these benefits and drawbacks.

Pros and cons of a king size mattress

Pros of a king size mattress

Cons of a king size mattress

Provides the most space for couples

Too large for small bedrooms

Lots of room for kids and pets

Tough to navigate through tight spaces

Aesthetically pleasing choice for large bedrooms

Higher price tag than other mattress sizes

Comfortable for working, reading, and watching TV

Can overwhelm a space

Is a king size mattress right for me?

Here, we’ll break down the top considerations you need to think about before buying a king size mattress.

Who will sleep in the bed

A king size bed provides more room for couples. Each sleeper gets about 38 inches of space to themselves. It’s an especially good option if one of you is a restless or active sleeper because you can comfortably move around without bothering your partner.

Desired comfort level

Since king size beds are usually shared by two people, you’ll need to take both of your comfort preferences into account. For those who can’t agree on a firmness level, consider a medium firm mattress as a middle ground. You may also want to consider a split king—that way, both of you can choose your preferred firmness.

In general, a softer mattress is ideal for side sleepers while a medium firm mattress is good for back sleepers. A firmer mattress is best for stomach sleepers.

Your room size

A king size bed is an excellent option for master bedrooms—ideally, you’ll want your bedroom to be on the larger side. At a minimum, a bedroom should be 10 x 12 feet for a king size bed; however, “the larger, the better” is a good rule of thumb when it comes to king size beds. Preferably, your bedroom will measure somewhere around 14 x 19 feet.

bedroom with king size bed in it and dimensions of room labeled with 19 feet wide by 14 feet long

Mary Brennan, interior designer and founder of House of Fine Design in New Jersey, shares a few design considerations to take into account, starting with the size of other furnishings in the room.

“With a king size bed, it’s very important to be sure you have bedside tables that are not dwarfed by the bed,” she says. “Typical night tables are 24 inches in width, but that’s really a bit too small—next to a king they feel a bit lost. An ideal size would be at least 30 inches in width, but never go less than 27 inches.”

Apart from issues of scale, a king size bed doesn’t impose many restrictions. In fact, Brennan says, a king size bed permits more flexibility in some design choices. Take bedside lighting, for example.

“Whether you choose a wall-mounted sconce or a table lamp, the key here is scale,” she says. “As long as the fixture is large enough to feel like it belongs, you could choose from a huge variety of styles and shapes.”

These are some other things to keep in mind when designing your bedroom around a king size bed: walk-around space, storage, and door swings.

Since a king bed takes a bit more planning and thought, you’ll need to confirm that the bed can make it around corners, down halls, and up stairs. This is when adjustable bases, box springs, and split king mattresses come in handy since they can be maneuvered more easily than an entire mattress on its own.

Next, you’ll need to decide where you’ll be placing the king bed in your bedroom. Jeffrey Phillip, interior designer and organizer in New York, starts this process by asking these questions: “Will the headboard still fit between windows? Can all the doors in the room still swing properly?” Additionally, if a client has a dog, he makes sure that there’s plenty of floor space where a dog can spread out if that’s his preferred sleeping spot.

Sara Raak, decorator and stylist based in Washington, D.C., uses this clever trick: “Take painter’s tape and tape out where the bed would go, making sure you have 3 feet of walk-around room, plus space for your furniture.”

Take into account other bedroom furniture too, like nightstands and a dresser. If the space is on the small size but you’re set on a king bed, Phillip recommends moving the dresser from the room or fitting it into a walk-in closet.

Storage is another big consideration when outfitting a room with a king bed. Since it does take up a great deal of room, that might translate to fewer storage pieces.

“The good news is that there are so many options for storage these days,” Raak says. “A platform bed can incorporate storage. A bedside table can too.”

Raak stresses the importance of wall storage, such as Ikea’s cult-favorite piece, the Billy bookcase, which comes in many different sizes and provides options such as doors or allows for two or more units to be configured in a space based on your needs.

Your body size

King mattresses provide plenty of space for heavier individuals and heavier couples. (Learn about the best mattress for heavy people.)

Your budget

King size mattresses are more expensive than other mattress sizes. They typically cost about 25% more than queen size beds of the same style and brand. A king size innerspring mattress will be the most affordable mattress type since they tend to run less expensive than other mattress types.

Temperature

If you tend to sleep hot, you may want to skip memory foam since it can trap heat. Innerspring and latex mattresses sleep the coolest.

Motion isolation

memory foam mattress is the best at reducing motion isolation. On an innerspring mattress, you may feel your partner moving around, which can disturb sleep. If you like the feel of an innerspring mattress but sleep with a partner, consider a hybrid mattress (such as a latex hybrid mattress) for reduced motion transfer.

Different types of king size mattresses

In this section, we’ll answer the question of whether king size beds come in other mattress sizes.

infographic showing the different dimensions of king, california king, wyoming king, texas king, and alaskan king mattresses

Standard king mattress

The standard king measures 76 inches wide by 80 inches long. For those with a partner who has differing sleep preferences, you can consider a split king, which is two twin XLs (38 x 80) side-by-side that come together to create a standard king.

California king mattress

A California king mattress measures 72 inches wide by 84 inches long. It’s 4 inches narrower and 4 inches longer than a standard king and tends to be a better option for taller people. With a California king, each person will get 36 inches of sleeping space. Also, it usually fits well in longer, narrower bedrooms.

Texas king mattress

A Texas king mattress measures 80 x 98 inches. It’s 4 inches wider and 18 inches longer than a standard king, and it’s the second largest king size mattress available.

Alaskan king mattress

An Alaskan king mattress measures 108 inches wide by 108 inches long—that’s 9 x 9 feet. As the largest king, it’s the biggest mattress size available. It’s 36 inches wider and 28 inches longer than a standard king.

Wyoming king mattress

A Wyoming king mattress measures 84 inches wide by 84 inches long. It’s 8 inches wider and 4 inches longer than a standard king mattress.

King size mattress vs. other mattress sizes

A king size mattress differs from other mattress sizes in many ways. You can compare these sizes and decide if you’d like to select one size over the other.

King vs. full


While a king measures 76 inches wide by 80 inches long, a full mattress comes in at 54 inches wide by 75 inches long, making it much less wide than a king. A king will provide ample room for couples, but a full mattress could be a tight squeeze if you’re sharing it with a partner. A full mattress is generally a better pick for solo sleepers.

King vs. queen bed

What's the difference between a king vs queen bed?

A queen is the second-largest mattress size on the market. Queen mattresses measure 60 x 80 inches, making it 16 inches smaller in width than the king mattress. A queen mattress will fit better in a smaller sized bedroom, a place where a king might not be able to fit. A queen will also provide room for storage furniture while a king might not permit such pieces if the space is diminutive.


King vs. split king

The only main difference between a king and a split king is that a split king is made up of two mattresses that come in at king size dimensions. This is an ideal pick for couples who each have their own mattress preferences. For example, one person might want a firm mattress while the other desires a soft mattress. The other bonus is that you won’t feel your partner while you sleep.

When it comes to pairing king and split king mattresses with an adjustable base, there’s a slight difference in how the two work. With a standard king size bed, the head and feet of the mattress move together on an adjustable base. With a split king, the head and feet move separately on an adjustable base. This pairing offers more customization for couples. 

Benefits and drawbacks of a split king vs. traditional king size mattress 

When would it make sense to choose a split king over a standard king and vice versa? Here’s how to tell which one is right for you.

Benefits of a split king mattress over a standard king

  • A split king offers more customization for couples. Do you like it firm but your S.O. prefers a softer sleep surface? If you and your significant other have divergent opinions on what mattress comfort level feels best, then a split king mattress could be the answer. Getting a split king means you can choose two different firmnesses, so you each end up with what you want. If you pair the mattress with a split king adjustable base, this will allow each of you to raise your head and feet separately. (Check out our split king adjustable mattress for couples.)
  • A split king does an excellent job at isolating motion. A split king mattress eliminates motion transfer because you're technically on two separate sleep surfaces. This is a particularly good feature if you or your partner is a combination sleeper—someone who switches positions throughout the night. Being on two separate mattresses means you won't disturb each other if you move around while you snooze.
  • A split king is easier to move. A king size bed is tough to navigate through tight spaces. Since it is so big, you may not be able to get it up a narrow staircase or around corners. That's when you can consider a split king, which gets you the same size sleep surface but in the form of two twin XL mattresses, which are much easier to move.

Drawbacks of a split king mattress over a standard king

  • It’s harder to snuggle on a split king. The split in the middle of a split king mattress can be inconvenient for couples who like to cuddle. You and your partner will be separated by the division in the middle of the mattress.
  • A split king requires special sheets. You’ll need a single top bed sheet that covers both mattresses and two fitted sheets that individually cover each mattress. While you can find split king sheet sets, they aren't as common as standard king sheets. (Here's how to choose the right sheets for a split king mattress.)
  • A split king is more expensive than a standard king. Depending on where you buy your mattress, you may end up spending a few hundred dollars more for a split king mattress vs. a regular king.

Other mattress sizes

Still need to shop around? We have plenty of convenient mattress size guides that can help you in your mattress-buying quest.

King bedding sets and accessories

You’ve finally settled upon a king mattress. Now comes the practical-meets-fun part: choosing the bedding you’ll need along with your foundation.

  • Sheets: King sheet sets typically come with a flat sheet, a fitted sheet, and two pillowcases. Note that for non-standard king mattresses, it may be more difficult to find sheet sets since those mattress sizes are much less common. (Try this organic percale sheet set.)
  • Pillows: A king size pillow is the best option for a king size bed. Most king size pillows are 20 x 36 inches, however, there is some variation depending on the brand. Two king pillows will fit perfectly across a king size bed. Keep in mind that you will need a king size pillowcase for a king pillow. (Check out this ultra-supportive latex pillow.)
  • Mattress protector or pad: For any mattress, a waterproof mattress protector can help protect your bed from bed bugs, allergens, and more. A mattress pad, meanwhile, works well as a barrier against spills and stains.
  • Mattress foundation: A king mattress can be paired with several foundation types—just be sure to double-check with the manufacturer to see what your mattress is compatible with. A traditional box spring foundation used to contain actual springs in a wood box, but today, it’s more of a fabric-covered or exposed wood frame that supports the mattress and creates a comfortable height for your bed. A platform bed is a modern option meant to be used without a foundation since the mattress rests directly on the platform. An adjustable bed base will work as well—and pairing a split king with an adjustable base delivers the most customization for couples.

King size mattress FAQs

Mattress shopping can feel daunting, which is likely resulting in plenty of questions around king size bed dimensions. These answers will help you during the process.

Is there a bed bigger than a king?

Some non-standard king sizes are bigger than a standard king. They include the Texas king (80 x 98 inches), the Alaskan king (108 x 108 inches), and the Wyoming king (84 x 84 inches).

What’s the difference between a king size and an Alaskan king size bed?

A standard king mattress measures 76 inches wide by 80 inches long. An Alaskan king is much larger. It measures 108 x 108 inches. That means it’s 36 inches wider and 28 inches longer than a traditional king.

What’s the difference between a California king versus a king?

A California king measures 72 inches wide by 84 inches long, while a standard king measures 76 inches wide by 80 inches long. A California king is 4 inches narrower and 4 inches longer than the standard king.

Do two twins make a king?

Two twin XL mattresses make a king—a single twin XL is 38 by 80 inches. When you pair two together, you get a split king, which measures 76 x 80 inches.

What’s the ideal amount of room space for a king size mattress?

The preferred bedroom size for a king size mattress is 14 x 19 feet. This size room will allow you to comfortably fit other furniture, like two nightstands on either side of the table, a dresser, a TV stand, etc.

How big is a king size bed frame?

A standard king size bed frame measures 76 inches wide by 80 inches long.

Is a bigger bed really better?

A more sizable bed is better for couples, larger bedrooms, and families where kids and pets like to pile up in bed. It will allow each of you plenty of space to snooze comfortably.

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