Twin XL vs. Split King: Is a Split King Two Twin XLs? + Key Differences

Key Takeaways

• Twin XL mattresses measure 38-by-80 inches and are commonly purchased for children, young adults, or shared guest rooms.
• Split king mattresses measure 76-by-80 inches — the same dimensions as a standard king. They’re best for couples with different comfort preferences and pair well with adjustable bases.

Twin XL and split king mattresses may be less common than other standard bed sizes but both make great options for those with specific sleep needs.

The main difference between a twin XL and split king is that a split king is double the width of a twin XL, meaning two separate twin XL mattresses create a split king bed. Independently, one twin XL mattress is a narrow bed recommended for one sleeper, while the split king is wide enough to fit two.

Rest Easy With Purple

Discover the difference of the GelFlex® Grid, which offers even support and comes in every standard size.

Shop Mattresses

Below, we answer some of the most common questions about the twin XL vs. split king. If you’re starting your online mattress shopping journey, we’ll help you understand the differences between the two so you’re fully prepared to make the best decision for your sleep needs.

Twin XL vs. Split King Size Comparison

What Is a Twin XL Mattress?

Dimensions: 38-by-80 inches

A twin XL mattress has the same width as a twin mattress but is 5 inches longer, making it more suitable for taller sleepers. Given their narrow width, twin XL mattresses make for excellent detached and bunk beds in small kids' bedrooms or college dorm rooms.

• Room size: The minimum ideal space for a twin XL is a bedroom that measures 8-by-10 feet.
• Cost: Twin XL mattresses cost between $100 and $3,000, depending on the material and quality of the bed.

Who Should Sleep on a Twin XL Bed?

Twin and twin XL mattresses are designed for single sleepers who have narrow bedrooms. Generally, these two mattress sizes are good fits for kids, teens, and single adults on the petite side. Twin XL mattresses are longer than twin mattresses by 5 inches and, as such, recommended for tall children and teens who require more legroom to stretch out.

Adults who like to spread out more may want to choose between a twin XL and a full bed. Taller individuals may prefer the extra legroom with a twin XL over the added width of a full.

What Is a Split King Mattress?

Dimensions: 76-by-80 inches

A split king mattress consists of two twin XL size mattresses joined by a metal bar, elastic strap, and/or a fitted bed frame. Split king mattresses are often used with specially made split king bed frames that are adjustable on each side. 

Split king and king mattresses both measure 76-by-80 inches. When separated, each of the two halves of a split king mattress measure 38-by-80 inches, the same as a twin XL. Split king mattresses require more bedroom space than most mattresses.

• Room size: The ideal space for a split king mattress is a bedroom that is at least 12-by-12 feet.
• Cost: Split king mattresses cost anywhere from $1,500 to $8,000 — a few hundred dollars more than the average king size mattress.

Although most split kings are two entirely separate twin XL mattresses, some retailers make split top variations where the mattress elevates independently at the head but connects at the foot of the bed.

Who Should Sleep on a Split King Bed?

Couples who want more personal sleeping space or to avoid feeling motion transfer could all benefit from sleeping on a split king mattress. For some couples' sleeping positions, a split king may prevent cuddling but improve sleep quality.

Couples who have different sleeping preferences might also benefit greatly from a split king size bed, especially if they pair their mattresses with an adjustable base. Adjustable bed frames allow each person to adjust their side of the bed separately, giving them more control over how they want to sleep at night.

Essentially, sleeping on a split king mattress is the closest thing you can get to sleeping on separate mattresses without having two separate beds in your room.

Do Two Twin XLs Make a King?

Two twin XL beds together make one split king, which equals the same dimensions of a standard king mattress. Split king mattresses are also called "twin king" or "dual king" mattresses.

To create a split king, you’ll need to: 

1. Decide if you will use one king bed foundation or an adjustable split king base.
2. Optional: Place a rubber mattress pad on top of the foundation and underneath the mattresses. This can prevent the two mattresses from sliding apart due to your movement.
3. Push the two twin XL beds together as close as possible. 

If you’re using a king foundation or bed frame — adjustable or not — you may want to take a few extra steps to cover the crack in the split king bed. This includes making the bed with:

• A bed bridge connector to fill the space
• Mattress straps around the bed’s perimeter
• A king sheet set 

Separate sheet sets aren’t necessary for a split king if both sides of the mattress remain at the same elevation at all times by way of either a flat foundation or a standard king adjustable base. Those using a split king adjustable base should opt for twin XL sheets, which have two separate fitted and flat sheets. Split top king mattresses require specially made sheets that can be difficult to find.

Considerations for Choosing a Twin XL vs. Split King

When deciding between different mattress sizes, remember to keep the following factors in mind.

Number of Sleepers

Not all bed sizes can accommodate more than one person (like the twin XL), so if you're sharing a bed with a partner, make sure to choose a size that's big enough for both of you. Split kings make a suitable bed size for couples whose sleep preferences differ, but when paired with an adjustable base, a split king is not recommended for those who co-sleep with children or pets.

Sleeper Height and Weight

Both twin XLs and split kings fit tall sleepers well — unless you’re taller than 6 feet 4 inches, which, at that point, you may want to consider a California king. Single sleepers of average build can fit comfortably on a twin XL, but those with larger body frames or heavier weights may sleep better in a full or queen bed. 

Bedroom Size and Layout

Before you go bed shopping, measure your bedroom so you know what size bed to get for the space you have and don't accidentally get a bed that is too big. Allocate ample floor space not only for your bed but also for walking space and furniture. 

Below are the minimum bedroom sizes for each popular bed size:

• Twin: 7-by-9.5 feet
• Twin XL: 8-by-10 feet
• Full: 9-by-9.5 feet
• Queen: 10-by-10 feet
• King: 12-by-12 feet
• California king: 11-by-13 feet

Sleep Preferences and Style

Consider your comfort preferences and sleep style to choose a mattress accordingly. Both twin XL and split king size beds are suitable for side, back, and stomach sleepers, but combination sleepers who toss and turn throughout the night may sleep better in a larger bed.

Most mattress sizes come in varying levels of comfort and materials, but couples may have a harder time compromising on these factors. While a twin XL mattress isn’t ideal for two sleepers, you may be deciding between a split king (two twin XL mattresses) or one standard king. If so, you may want to choose a split king to satisfy both sleepers’ needs for:

• Mattress firmness: If you don’t agree on a balanced firmness, a split king allows you to tailor the firmness for each side of the bed to comfortably support both sleepers. 
• Material type: Different types of mattresses offer unique feels and support. If one partner likes the conforming feeling of memory foam while the other prefers the buoyancy of latex, opting for two separate twin XL mattresses creates a custom sleep experience for everyone.

Bed Frame Material and Design

Although they're standard sizes, twin XL and split king beds are less common than other sizes, so you may have trouble finding these bed frame sizes and bedding. Some retailers also only sell twin XL mattresses in pairs with split king bed frames to match. 

Keep in mind that some bed frames are bulkier than others, especially if they have embellishments such as headboards, footboards, and pull-out drawers. If you're buying beds for compact spaces, make sure to pick out a bed frame design that doesn't take up too much space. Minimalist platform beds with no headboards are a good option for small bedrooms.

Budget

How much you’re willing to spend on a mattress plays an important role in what size mattress you can afford. A split king naturally costs more than a single twin XL because they’re two mattresses and double the size. 

Couples with lower budgets may find a queen or king bed suitable instead of a split king. Single young adults with lower budgets may find that a twin XL fits their needs instead of choosing a larger size like a full. 

Other Standard Bed Sizes

Some retailers make a range of different king size beds and twin variations for specific needs, but there are only six traditional bed sizes commonly found in stores with easy-to-find accessories. Compare twin XL and split king beds to other popular bed sizes with the chart below:

Find Your Perfect Fit With Purple

When choosing a mattress, it’s important to know the various mattress sizes available and how they compare to one another. Although twin XL and split king mattresses appeal to different mattress buyers, you now know how many twin XLs make a split king bed and how many people fit in each.

Purple offers mattresses in all standard sizes, each built with innovative sleep technology. Our GelFlex® Grid cradles your body exactly where you need support so you can sleep comfortably and wake up refreshed.

Maximum Comfort and Support

With our GelFlex Grid®, Purple mattresses provide targeted, adaptive support.

Shop Mattresses