What Is a Split King Mattress?


Split king mattresses aren’t the most common mattress option, but they can be a good choice for some buyers, especially if it's time to get a new mattress.

We’ve spent a lot of time working to create great mattresses, and we know that people have different tastes and needs. So, we decided to write this guide to help you understand your options.

Here's what you should know about split king mattresses, including size details, benefits, drawbacks, and other considerations.

What Are Split King Mattresses?

Split king mattresses are two XL twin mattresses pushed together or a single king-size mattress with adjustable left and right sides.

These mattresses work best for couples with significantly different sleeping preferences and can’t easily compromise on mattress firmness. It’s important to remember that sleeping preferences can have real impacts on your health.

Split king mattresses are far more common among couples because their unique traits aren’t appealing to most individuals.

How Large Are Split King Mattresses?


Typical split king mattresses are 80 inches long, with two 38” sections side-by-side. They fit into the same bed frames as regular king mattresses.

One important thing to note is that split king mattresses are only available in 80-inch formats. You can’t make a split California king mattress, as those are 84 inches long and somewhat narrower than two twin XL beds. Exceptionally tall people may not be able to get a split king.

Benefits of a Split King Bed

There are several benefits to having a split king mattress instead of a traditional single option.

Flexibility In Materials

Consumers have a wide range of preferences for bedding materials. Pillow-top mattresses are the most popular choice. There’s a high probability that couples will like different bedding materials, and split kings allow each person to enjoy what they want.

The same goes for mattress toppers, which are popular regardless of bedding type. Some people prefer memory foam toppers, while others like pillow tops or natural latex. Split kings make it easier to customize bed choices without sacrificing a partner’s ability to do the same.

Moving Mattresses

Moving two twin XL mattresses is significantly easier than transporting a single king-size mattress. They’re far easier to get upstairs and around corners. They’re also much lighter than a larger mattress, which can be challenging to move.

Twin XL mattresses can easily fit in most bedrooms. However, some home designs may make it impractical to fit a king-size mattress. 

Limited Motion Transfer

Adjustable split king mattresses are excellent for blocking motion transfer. Modern materials like memory foam are already good at blocking motion, but using split mattresses allows for even less motion transfer. This design also helps if using an innerspring mattress, which can cause more movement.

Limiting motion transfer can significantly improve sleep. It helps to prevent waking up from unwanted movements and sounds. 

Advanced Features

For the ultimate comfort and luxury, try a split king mattress with an adjustable base. Once you can raise and lower your side of the mattress to help with your sleeping position or assist in getting out of bed or sitting up to read or watch tv without disturbing your partner, you’ll never go back. Some adjustable frames also offer massage modes, power outlets, and drink holders.

How Do Split Kings Compare to Other Mattresses?


  • Twin mattresses are the smallest option. Theyare about 5 inches shorter than a king-size bed and far narrower, making them the most popular choice for children who have outgrown a crib.
  • Twin XL mattresses aren’t any wider than regular twinsbut have an extra 5 inches in length. This length makes them tall enough for most single adults and older children. These are a popular choice for dorm bedrooms, and they are half the surface area of a king-size bed, making split kings possible.
  • Full mattresses are the same length as twinsbut about 15 inches wider. This is the first mattress size suitable for couples, although they usually require close cuddling to be comfortable.
  • Queen-size mattresses are about 60 inches wide, about half a foot wider than most full-size mattresses. This is wide enough for most couples to enjoy sleeping separately, making it a popular choice in many households.
  • King-size mattresses are the biggest standard option. They’re 76 inches wide, more than a foot wider than a queen, and almost certainly enough to give each sleeper plenty of room. Split kings match this size.
  • California king mattresses are a variant. They’re a little longer than kings but only 72 inches wide, making them more suitable for taller


While split king mattresses have many benefits, there are also some drawbacks to the design. Split kings aren’t for everyone, so if any of these seem like a deal-breaker, it’s best to stick with a regular mattress instead.

Split Kings Can Look Weird

Split king mattresses might not be easy to spot if the mattresses are the same height and you use a single large sheet for the whole bed, but they’re easy to see if they’re of very different heights or if you have separate sheets and blankets. The result can be comfortable but may not look as appealing as a single bed.

There’s a Crack

Another important detail with this type of mattress is a clear separation between the two halves. This line is especially noticeable on mattresses with poor side support. As one moves towards the inner edge, you’ll roll down slightly and find yourself against a cliff a few inches high where the other mattress is. This can be both noticeable and distracting.

The same crack can also make it hard to enjoy cuddling or other activities in bed. Split kings are excellent for sleeping but lack versatility.

However, there are two ways to mitigate the impact of the crack between the mattresses.

The first option is to have a single bed with adjustable sides. Each user's split is primarily internal and flexible in this format, so there’s no crack on the top of the mattress to worry about. Mattresses that offer this are expensive.

The second option is using a mattress with reinforced sides that avoid sagging. No mattress can be soft enough to remain comfortable and firm enough not to sag when you move to the edge, but sturdy edges limit the amount of dipping if you move to the middle of the mattress.


Finally, split king mattresses can be more expensive than a single large mattress. If you look at pricing for two mattresses of the same type, a king will cost less than two twin XL mattresses. Realistically, the price difference can be several hundred dollars or more.

However, the cost isn’t as impactful if you buy different mattresses. If one sleeper wants a high-quality luxury mattress and the other is fine with a basic memory foam mattress, that could be far more affordable than getting a single large luxury mattress.

Final Thoughts

Split king mattresses are a relatively rare choice for bedding. As you read the pros and cons above, understand that there are many benefits and drawbacks compared to traditional mattresses. Take your time to talk it through with your partner to figure out what mattress style is best for you.

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