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King vs. Split King Mattress: Which Mattress Size is Right for You?

King vs. Split King Mattress: Which Mattress Size is Right for You?

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Mattress Guides
Read Time: 6 minutes

The biggest standard mattress sizes—the king and split king—are the same size and price, but the primary variation between these two mattresses is their construction. King mattresses are one single bed, while split king mattresses are two beds pushed together, equaling the size of a king.

Our guide explains the similarities and differences between kings and split kings so you can determine which will work better for you and your home.

What is a King Size Mattress?

King mattresses, also called Eastern kings, are the widest standard bed. They measure 76 inches wide by 80 inches long and have 6080 square inches of surface area.

These beds are a great option for couples who have similar firmness preferences and want lots of space to spread out. Individual adult sleepers who have lots of space and want a luxurious bed can also use a king bed, but they don’t necessarily need one.

King size bed frames and accessories can get quite expensive due to how big they are, typically costing between $700 to $4000. Your bedroom should be at least 12 by 12 feet to accommodate a king bed so you still have space to walk around and fit other furniture in the room. It’s unlikely a king bed will fit in a small space, such as studio apartments.

Benefits of Choosing a King

Many people enjoy king beds for the amount of space there is to stretch out. They work well for couples, co-sleeping families, and large bedrooms.

Large Enough for Couples

King vs. Split King Mattress

While queen mattresses are a common option for couples, king mattresses offer much more personal space and are more comfortable in the long-term. For couples who both enjoy stretching out, king mattresses are a great option.

Works for Co-Sleeping Families

Families who enjoy co-sleeping or cuddling in bed with their child might prefer a king mattress so they can comfortably sleep together. With this in mind, king mattresses are only big enough to fit two adults and one small child at most.

Suits Large Master Bedrooms

If your bedroom is 12 feet by 12 feet or bigger, a king mattress can make for a great focal point in the center of the room.

Compatible with Adjustable Bed Frames

King beds—and other standard mattress sizes—are compatible with high-quality adjustable bed bases, motorized bed frames that allow you to elevate the top and foot of the bed to any angle you prefer. Adjustable bed frames are not only comfortable, but they have many health benefits, including reducing back pain, reducing sleep apnea symptoms, and improving circulation.

What is a Split King Size Mattress?

Split king beds have the same dimensions as a standard king, only the mattresses are split into two separate beds rather than being one single unit. The two mattresses are the equivalent of a twin XL size mattress, at 38 by 80 inches each.

Split kings are one of the best mattresses for couples with different firmness preferences and who want a split adjustable base. However, split king beds aren’t necessary for single adults since their main function is to suit couples.

One of the main drawbacks with the separate mattresses is there’s a noticeable gap between the two beds. So, if you and your partner ever decide to sleep closer together, the gap may make that uncomfortable.

Since a split king and an Eastern king bed share the same dimensions, they fit in the same sized bedrooms. Split kings and regular kings are usually about the same prices as well, though some brands might charge an extra hundred dollars or so for a split king.

Benefits of Choosing a Split King

Split kings are great for couples since they can share a bed while also enjoying personal space. Plus, they can each choose a mattress suitable for their body types.

Helpful for Couples With Different Sleeping Styles

One of the primary benefits of a split bed is that they suit couples who are entirely different sizes with different sleep styles.

Say you weigh less than 130 pounds and are a side sleeper, but your partner weighs over 230 pounds and is a stomach sleeper. If so, you would both need very different mattress types to be comfortable. With a split king bed, you could have a soft mattress while your partner has a firm mattress, all while still sleeping close together.

Pairs with Split Adjustable Bed Frames

A luxurious accessory for split king mattresses is a split adjustable frame. Like standard adjustable frames, you can elevate your head and feet, but with a split adjustable frame, both halves of the frame move independently. This way, you can adjust your bed without disturbing your partner.

Eliminates Motion Transfer

Motion transfer is a common issue for couples sharing a bed. When your partner gets in and out of bed or switches positions, their movements can transfer to your side of the bed, potentially disrupting your sleep or throwing you out of your comfortable position. Having two separate mattresses eliminates this issue, as one mattress’s movements won’t impact the other’s.

Easy to Transport

With a split king mattress, you’re working with two small mattresses versus one huge one. Twin XL mattresses are much lighter and thinner than king mattresses, so they fit through doors and even in some pick-up trucks. If you ever move homes or choose to rearrange your bedroom, you can transport the individual mattresses without difficulty.

Similar Mattress Sizes

If a king and divided king don’t seem to fit the bill, what are your other options? Some similar mattress sizes to a king or split king bed include a queen, California king, and a split California king mattress.

Queen Size

Queen mattresses are 60 inches wide and 80 inches long and are the most popular mattress option for single adults. Queen beds also work well for couples who have a small master bedroom or enjoy sleeping close together. A queen size mattress is also a good size for guest rooms.

Since queen mattresses are smaller than kings and split kings, they’re more budget-friendly.

California King Size

A California king size mattress is 72 inches wide by 84 inches long, making it 4 inches longer than standard kings, but also 4 inches narrower. People mistakenly assume Cal kings are bigger than kings, but they have a smaller surface area of 6048 square inches. We recommend getting a Cal king mattress if you’re a taller individual or have a narrow and long bedroom.

Split California King Size

Similar to the king mattress, California king mattresses come in a split variation. Although split California king mattresses are not as common as split king mattresses, they are a good option for tall couples with different firmness needs. You can also find split California king adjustable bases, but again, they are uncommon.


Is a king mattress the same size as two twins?

No, king and split king mattresses are the same as two twin XL mattresses side by side. Conversely, two standard twin size mattresses pushed together are 76 by 75 inches, which is 5 inches shorter than a king bed.

You can push together two twin mattresses if you choose, but you might struggle to find perfectly matching accessories for them because two twin mattresses together do not equal a standard mattress size.

Is a king mattress too big for one person?

While a single person can purchase a king mattress if they want to, it’s not necessary. Queen mattresses are more than enough for a single person. It’s unlikely a single person would be able to take up all the space on a king bed, but if you have a big enough bedroom and a comfortable budget, nobody’s stopping you from getting one.

What kind of sheets do you put on a split king bed?

Since split kings have a rather unique construction, they need special bedding to suit them. You should use twin XL fitted sheets for the individual mattresses, then one king flat sheet and comforter on top of both mattresses.

You can find split king sheet sets with all of this included, but they are a bit rare. So, you’ll most likely have to buy the individual sheets for your split king, which can get expensive.

How do you keep a split king bed together?

Most split king beds come with an iron plate connector to keep the beds together, but if you DIY’d your split king and bought two twin XL beds separately, there are other solutions you can try.

An easy way to keep a split king mattress together is by using a fitted bed frame. The railing will keep the two mattresses in place, minimizing the risk of them slipping out of place or coming apart.

You can also use a non-slip mattress pad or dual-sided tape between the mattresses and the foundation. The resistance from the padding or tape will stop the mattresses from shifting.

Do you need different sheets for an adjustable bed?

King and split kings are both commonly paired with adjustable bed bases. With an adjustable bed base, you should ideally get fitted sheets with extra deep pockets or sheet suspenders. This way, the fitted sheet is secured to your bed and won’t pop off in the middle of the night.


Although king and split king mattresses are the same bed size, split kings aren’t necessary unless you share a bed with somebody who has different firmness needs. Split king beds are also a great choice for couples who have different schedules and don’t want to disturb each other when getting in and out of bed.

King mattresses work well for couples with similar firmness preferences. Single adults can use a king bed if they choose, but this size of a bed isn’t always necessary for solo sleepers.

Harrison Wall is Sleep Junkie’s business strategist and sleep analyst. He also authors posts on bedding and mattress accessories. Harrison regularly coordinates with new mattress companies and tests their products to determine what really helps you get better rest and have brighter mornings.

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