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Split King vs. Split Top King: What's the difference?

Split King vs Split Top King

There is a lot of confusion around Split King and Split Top King sheet set sizes. People mistakenly believe that there is no difference, and end up buying the wrong sheets. This misconception is mainly because both sizes share the same dimensions as a standard king (76 in x 80 in). However, the length of the split on the mattress is what completely sets them apart.

A Split King mattress consists of 2 Twin XL mattresses. A Split Top King mattress is a regular king with its head split by 34-36".


What is a split king size?

A split king mattress is completely split down the middle. It is made up of 2 Twin XL mattresses pushed together, forming a standard king-sized bed.

  • Twin XL Mattress Dimensions: 38 x 80 inches
  • Split King Mattress Dimensions (2 Twin XL’s): 76 x 80 inches

A Split King Sheet Set consists of 2 Twin XL fitted sheets, 1 flat sheet, and 2 pillowcases.

Any couple who has ever tried to buy a mattress together knows how difficult it is to choose one that fits both sleeping preferences. Someone usually ends up with neck and or back pain, which makes separate mattresses an ideal choice. This is also a cheaper alternative to getting a king bed with an adjustable mattress.

What are the pros and cons of a split king mattress?


  • Freedom in choosing the firmness of the mattress for your side.
  • Less motion transfer, leading to uninterrupted sleep.
  • Easier to lift two twin XL mattresses than a king-sized mattress.
  • Option to upgrade to a motorized adjustable frame*

*This gives couples the ability to separately customize the incline and tilt level of the head and footer.


  • No sleeping in the middle because of the split.
  • Uneven firmness levels may make it uncomfortable to be close to your partner.
  • Dressing the bed with fitted sheets can be a hassle because of the split.
  • If you are taller than 6ft 1in, you won't be comfortable (in which case a split cal king would be the better choice.)


What is a Split Top King?

Split top king mattresses have a top split. This means that the upper portion of the mattress is split and the lower portion is connected.

They can come in 3 sizes: Split Top King, Split Top California King, and Split Top Queen.

This mattress size is fairly new. However, it is starting to get popular with couples that have different sleep preferences and still want the feeling of “togetherness.”

Split Top King Mattress Dimensions: 76 x 80 inches

Top Split Length: 34-36 inch

A split top king sheet set consists of 1 split top king fitted sheet, 1 flat sheet, and 2 pillowcases and you can purchase them here.

Depending on the brand, you might come across these alternative names, but they are exactly the same size:

  • Sleep Number calls theirs FlexTop King
  • Personal Comfort calls theirs FlexHead King
  • Saatva calls theirs Upper Flex King
  • Other known names: Split Head king, Top Split, and Split King

A split top king (or flex top king) mattress comes with a motorized adjustable bed frame. This frame makes it easy to customize the incline of the upper left or right side of the mattress. Each side can rise individually while air chambers are used to customize the firmness.

Unlike a split king, an adjustable frame is not optional. Without the motorized frame, there is no point in getting a split top king because it defeats the purpose of its main feature: the top split.


  • Only 1 fitted sheet is needed instead of two (split king).
  • An adjustable top half, independent of your partner’s preferences.
  • Air chambers, meaning customizable firmness levels.
  • Experience the feeling of togetherness.


  • The cost of accessories is expensive*
  • No point in buying a flex top king if you don’t have the motorized frame.

*Affordable split top king sheets are hard to find. Sheets from Sleep Number are $200+, but you can find alternative sheets for $69.95-$89.95 right here.


What to consider

Sleeping Preferences

    One of the most common problems is agreeing on a mattress. One person almost always ends up with neck and or back pain while the other sleeps perfectly well.

    If this is you and your partner and you both can’t agree on a mattress because of firmness levels, then the best solution is to get a bed with split mattresses or an adjustable bed. In this case, either size would work.


      If price is an issue, a split king bed is a perfect choice. You can purchase a king-sized frame with a supporting baseboard and go on the hunt for 2 twin xl mattresses (that are the same level of thickness).

      If you have more room in your budget or you need inclination support for a better sleep, then a split king or split top king mattress would suit your needs.


        Before buying any mattress, you have to make sure there is enough space in your room. The ideal room space for a split king and split top king mattress is the same as a king, at least 10 feet by 12 feet with a recommendation of 13 feet by 13 feet.

        These measurements factor in space for two nightstands and a dresser. Anything smaller can lead to an overly cramped room with little walking space.


        FAQ - Split King

        Where can I purchase a Split King Mattress?

        A split king mattress is much easier to find. All you need is a king sized frame and 2 twin xl mattresses.

        If you want an adjustable split king mattress, here are a few well known companies:

        Is a split king adjustable bed worth it?

        A quality night’s sleep leads to better health and productivity. So if you or your partner are having a hard time sleeping, an adjustable bed is worth it.

        What kind of sheets do you use on a split king?

        You can purchase a split king sheet set or build one yourself by buying the individual items separately. All you need is:

        • 2 twin xl fitted sheets
        • 1 king sized flat sheet
        • 2 king sized pillowcases (or queen if you have standard)

        What sheets do you use on a split king adjustable bed?

        A regular split king sheet set with a good quality elastic, will work.


        FAQ - Split Top King

        Where can I purchase a Split Top King Mattress?

        You can purchase a split top king size mattress from one of the following companies:

        Currently, these are the only three well-known companies that produce this kind of mattress.

        Where can I find split top king sheets for a sleep number bed?

        Split top king sheets are hard to find. Sleep number sells theirs at an expensive price. However, now that the mattress size is gaining popularity for adjustable base, there are some bedding companies that have started producing this size. You can find some of the most affordable split top king sheets here.

        Is there luxury split top king sheets?

        If you are looking for the most luxuriously affordable split top king sheet set, Westlake Home is your best bet.

        Their sheets are Italian-made, OKEO-TEX certified organic. The only downside is that they get out of stock pretty quickly.

        Aside from them, you will have to purchase directly from the company that sold you your mattress because this size of bedding is difficult to find.

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