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King Size Bed Dimensions: How Big is a King Size Bed?

The tossing. The turning. The snoring. The cover-stealing. These and other partner disturbances are some of the most common reasons we often get a poor night’s sleep. So, what’s the best way to solve these issues? A bigger mattress, of course! A king bed may be just what you need.

King size mattresses are not all the same and dimensions can vary by country. In the United States, king size mattresses share the following dimensions:

King Size Bed Dimensions and Facts

  • Measures 76 x 80 inches – 16 inches wider than a queen-size mattress
  • Same size as two twin XL mattresses pushed together
  • Also known as an Eastern bed
Couple in small bed, man's hand sprawled out and in girl's face space.

Many couples make the mistake of buying a mattress that’s too small for them. They sleep on a full-size mattress and think they’re fine. They’re close. They can cuddle. And it’s called a “double” bed for a reason, right? But let’s do the math — if you’re sharing a double bed with your partner, you only have 27 inches each. That’s less than the width of a crib/toddler bed. Yikes! From snoring, to cover-stealing, to active sleepers, partner disturbance is one of the most common reasons for poor sleep quality.

Try this test to determine if your mattress is too small: You and your partner should be able to lie next to each other, put your hands behind your heads with elbows out – and not be touching. Most people are unable to do this in anything other than a king-size bed.

Twin/Single: US 38” x 75” EU 35” x 79”,  Full/Double: US 54” x 75” EU 55” x 79”,   Queen: US 60” x 80” EU 63” x 79”,  King: US 76” x 80” EU 71” x 79”, Cal King: US 72

Benefits of a King Size Mattress

Did you know that a King size mattress offers several health benefits? Many people suffer from insomnia, simply because they have so much trouble staying comfortable during the night. It’s hard to sleep well on a crowded mattress. A king-size mattress, with its increased surface area, makes sleeping comfortably through the night much more likely.

Below are some additional health benefits:

  • Better blood flow – You have a lower risk of waking up with uncomfortable pins and needles, thanks to being able to spread out comfortably in the extra space.
  • No restless legs – Large dimensions allow you to fully stretch out eases pressure on the ankles and Achilles tendons.
  • Breathing easier – When you sleep pressed up against your partner without enough space, your respiratory system can become compressed.
  • Less tossing and turning – Whether your partner is bothering you or you just don’t have enough space to get comfortable, a king-size bed will alleviate those issues and reduce tossing, turning and night waking. The larger your mattress, the less you feel your partner’s motions during the night, and vice versa.
  • Proper sleeping positions – When you have extra space, you can focus your sleeping habits on reducing joint tension, pain, and soreness, along with comfortably relieving pressure points.
Benefits of a king size mattress

Frequently Asked Questions About King Size Mattresses

What’s the difference between a king bed and a California king bed?
While a standard king-size bed is 76 by 80 inches, a California king measures 72 by 84 inches — making it 4 inches narrower and 4 inches longer.

A standard king size mattress is the same length as a queen mattress, and 5 inches longer than a twin and double mattress. That’s the big difference in the two king mattress types – the California king sacrifices the extra width of the standard king size bed for the extra length, which can better accommodate taller sleepers. For people over six feet tall, the California king can be a great fit – in fact, it’s a popular choice among professional basketball players and other tall people.

What’s the difference between a king size and an Alaskan king size bed?
For those who need even more sleeping space than a traditional or California king size bed can provide, there’s always the square-shaped Alaskan king bed, which measures a whopping 9 feet by 9 feet. You really have to do your homework on this one, though, to make sure your space can accommodate such a large mattress and bed frame. You’ll also have to research where to buy bed linens to fit an Alaskan king size bed. Most of the time, an Alaskan king mattress is purchased through a custom or specialty dealer rather than a traditional mattress outlet.

Do king size bed dimensions vary from country to country?
Yes, they do. In fact, names and dimensions differ across countries and regions for all size mattresses. But in most countries, the mattress dimensions of a king-size bed are either 76 by 80 inches or 76 by 60 inches.

Is a king mattress really worth the extra expense?
That all depends on how much you value your comfort and a good night’s sleep. Most owners of king size beds would tell you the expense is totally worth it. When you consider that we spend up to a third of our lives in our beds, you can’t afford to short-change your comfort and health.

What’s the ideal amount of room space for a king size mattress?
In the end, that’s totally up to you – it really comes down to personal preference. A lot of your space requirements will also depend on the kind of bed frame you choose and other furniture in the room. Of course, larger, more ornate bed frames will require more space, while simpler frames won’t take up much more room than the bare mattress dimensions. A good rule of thumb is that your room should be at least 12 feet square in order to comfortably accommodate your king-size bed. Some people prefer their bed frame to have at least two feet of clearance on all sides so that it doesn’t feel like it completely dominates a room.

Before you choose your bed frame and mattress, think about how you’ll move everything into your room. Besides the overall bedroom space, you also need to think about the sizes of your doorways, hallways, stairs, and corners to make sure moving your new mattress into your home is easy-breezy. Also, think about whether you’ll use nightstands beside your bed when determining whether a king will fit your bedroom space.

History of the King Size Bed

The king-size bed hasn’t always been the most popular mattress for couples. In fact, as recently as the 1940s, most Americans were sleeping on either a twin bed or a full-size mattress. Every now and then, the mattress industry may have promoted buying two twin mattresses and pushing them together – sometimes called a split king – but the idea never really took hold. That is, until around 1945, when mattress companies introduced the larger mattresses we know as king and queen.

Black and white photo of old-fashioned couple in separate beds, husband serving wife breakfast in bed.

Originally developed for west coast celebrities, the California king-size bed was the first major player on the market, followed several years later by the Eastern king, which eventually became the standard king size we know today.

During the 1950s, these larger mattress sizes surged in popularity. A big reason for this shift to larger mattresses is because Americans were actually getting bigger over time. They needed furniture to grow to accommodate them. Back in 1900, only 4 percent of American men were taller than six feet, but by 1959 that percentage had swelled to 20, with women growing taller at roughly the same rate. And in the post-World War II booming economy, these big Americans were buying big houses in the suburbs – which they enjoyed filling with big furniture.

Marketing from mattress companies didn’t hurt, either. September, traditionally known as “Better Sleep Month,” became “Measure Your Mattress Month,” dubbed so by the National Association of Bedding Manufacturers – which also coined the slogan, “Buy Bigger, Sleep Better!”

In 1953, king size bedding accounted for a mere 1 percent of all bedding sales in America, but by 1962, it represented a whopping 10 percent of all bedding sales across the country.

Is a Bigger Bed Really Better?

Most of the time, yes. Okay, just yes. In fact, studies have shown that couples sleep better when they have a bigger mattress size.

Mom, dad, and daughter relaxing in bed with beagle dog.

A twin bed is your smallest option, which is a great single bed for kiddos when they outgrow their cribs. Twin size mattresses make great bunk beds and guest beds, too, since they’re easy to store and good for when your bedroom space is tight. A full bed, despite being called a “double bed,” may sound like it’s a good fit for two people — but it’s really not. The sleeping space on a full mattress is too tight for couples and works better for single adults.

The popular queen size mattress provides value for couples who want to save space in their bedrooms and don’t mind sleeping a bit close together. Most sleepers would agree that the very best mattress for couples is a king-size bed. It’s amazing how much more comfortably you and your partner will sleep with just a few extra inches of bed space.

If you have a family, even better. Your king-size mattress leaves plenty of room for family snuggling and co-sleeping, and the extra width can help keep your youngest sleepers from falling out of bed. This includes your pets, too. You’ll have enough room for the whole gang on a king-size bed.

Best of all, the king size mattress can best accommodate certain sleepers, like the “starfish sleeper” – you know, the one who likes to fully sprawl out while asleep. And if that starfish is you, you can fully stretch out and sleep in any weird position that feels good – all without disturbing anyone else.

With the extra space, you and your partner are much less likely to feel one another’s motions during the night – and since the average person tosses and turns between 60 and 70 times per night, that extra distance is a real sleep saver. Because some health conditions – like arthritis or joint injuries – often can make sleep restless, it’s good to have all the room you need to move around, change position and get comfortable as needed without disturbing your partner.

If you’re a design geek, sometimes a bedroom space just looks better with a larger bed frame. Elements like symmetry and balance can make a king-size bed look perfect within a space, while a smaller bed can seem dwarfed within a large bedroom. Depending on the bed frame you choose, your king size mattress also can offer pretty generous under-bed storage space.

King Size Bed Dimensions

The time we spend in our beds is time well spent. We need sleep to recharge, relax, and renew, so it’s important to get a great night’s sleep every single night. Mattress size is a key ingredient for getting your best sleep, and people tend to sleep better on larger beds. Investing in a king size mattress is an important step toward guaranteeing restful, uninterrupted sleep both for yourself and your partner. And don’t forget the platform that helps your mattress give you support in all the right places. Go big and go home – you won’t regret it.