Updated April 25, 2026
King mattresses have long ruled couples’ bedrooms. They’re big enough to comfortably fit two people, even restless sleepers, along with a child and a pet or two. But there’s another mattress option you might not know about, one that may suit sleep partners even more: a split king.
In terms of size, there’s no difference between a king vs split king mattress. Both stretch 80 inches long and 76 inches wide.1 But unlike a king mattress, a split king is actually two twin XL mattresses pushed together, designed to solve the time-old argument between uncompromising sleep partners: firm or soft?
Explore the draws and drawbacks of standard king beds and decide if the split is worth it for you and your partner.
King mattresses have long ruled couples’ bedrooms. They’re big enough to comfortably fit two people, even restless sleepers, along with a child and a pet or two. But there’s another mattress option you might not know about, one that may suit sleep partners even more: a split king.
In terms of size, there’s no difference between a king vs split king mattress. Both stretch 80 inches long and 76 inches wide.1 But unlike a king mattress, a split king is actually two twin XL mattresses pushed together, designed to solve the time-old argument between uncompromising sleep partners: firm or soft?
Explore the draws and drawbacks of standard king beds and decide if the split is worth it for you and your partner.
What is a King Mattress?
Let’s start with the straightforward one: a traditional king mattress. (And yes, there is only one mattress that makes up a king mattress).
King mattresses are named as fittingly as a fitted sheet. They’re typically the largest standard mattress size available, standing (or lying) at a regal 80 inches long and 76 inches wide.1
The occasional, ambitious single sleeper may choose a king mattress, but they’re usually best suited for couples who enjoy sleeping in the same bed, but like their space, too.
Pros of a King Mattress
The main appeal of a king mattress is its impressive size. A larger mattress can benefit:
- Restless sleepers – Nighttime restlessness can be disruptive for both sleep partners. With a king, you can fit comfortably on your side of the bed, with enough space to toss and turn — and avoid accidentally kneeing your partner.
- People with children or pets – If you let little ones or furry friends in bed with you, a king mattress can ensure that all sleepers have enough room to snooze soundly. Learn why sleeping with your dog can be beneficial in our research-backed blog.
Cons of a King Mattress
With mattresses, bigger is better — for some. These important factors may demote a king size mattress:
- If you have a smaller bedroom, a king bed may take up too much floor space.
- King mattresses can be cumbersome to move.
- You and your partner must agree on the type of mattress you want.
The last point is often where sleepers run into the biggest issues. For couple sleepers, partners may not share the same tastes in mattresses. (They do say opposites attract, after all.)
If only you could split a king down the middle and tailor each side to each person’s unique preferences…
Wait a minute.
What is a Split King Mattress?
And we’ve arrived at the epiphany mattress designers came upon long ago when they decided to start smashing two twin XL beds together to create the split king size mattress. Let’s talk about how it compares to the OG king.
A split king mattress is technically two mattresses pushed together and placed on the same bed frame. Each half is a twin XL mattress, measuring 80 inches long and 38 inches wide.1
When the two twin XL beds are flush, they add up to the same length and width as a standard king mattress: 80 inches by 76 inches.
Pros of a Split King Mattress
A split king mattress allows both you and your partner to rule the bed equally. Here’s what sleepers love about them:
- Complete customization – By far, the greatest advantage of a split king is that you and your partner can sleep on a mattress you love. With Casper, not only can you select your ideal mattress firmness levels, but you can opt for other mattress perks like Snow Technology and Zoned Support on one side or the other.
- Movability – A split king is uniquely mobile in contrast to a king. Instead of lifting and maneuvering an entire king mattress, you can move two smaller twin XL mattresses — which will definitely fit through your bedroom door. This is especially advantageous if you and your partner move frequently, or you enjoy routinely changing your bedroom layout. Learn more about how to move a mattress in our blog.
- Reduced motion transfer – One of the standout benefits of a split king mattress is the significant reduction in motion transfer. Since each side of the bed is a separate mattress, movements from one partner are less likely to disturb the other, leading to a more restful night’s sleep.
A split king can further enhance your sleeping experience if you put it on an adjustable bed frame.
The Casper Adjustable Base Max allows both you and your bedfellow to lie in virtually unlimited positions at the touch of a button. Fully unwind before bedtime with 4-Zone Massage, and create your ideal sleep conditions with the Zero Gravity and Anti-Snore presets.
Cons of a Split King Mattress
What might cause the biggest split in opinion between you and your partner over this mattress option? The split itself.
While the two twin XL mattresses lie snug against each other on the bed frame, there will still be a noticeable split where they meet. You or your partner may dislike this for a few reasons:
- You may feel uncomfortable if you turn over onto the split during the night
- It may make cuddling in the center of the bed less comfortable
What Sheets Do You Use for a Split King?
As the split king bed itself is fully customizable, so are split king sheets. Here are your main options:
- Standard king sheets – Since split kings and standard kings share the same dimensions, you can use the same sheets for both. Covering both mattress halves with a single king-sized sheet may also help hide and minimize the center split.
- Two sets of twin XL sheets – Do you and your partner also have differing sheets preferences? Whether you like to sleep on cotton, silk, or flannel, you can each make the bed with the sheets that make you feel the coziest. Learn more about flannel vs cotton sheets in our blog.
Do Split California King Mattresses Exist?
Yes, split California king mattresses do exist, though they are less common than standard split king mattresses. A split California king mattress has the same overall dimensions as a regular California king mattress – 72 inches wide by 84 inches long. However, it is divided down the middle into two separate mattresses, each measuring 36 inches wide by 84 inches long.
Choosing Between a Split King vs King: Key Differences to Consider
If you and your partner are split on the split king vs king decision, talk it out together. Consider both of your:
Firmness Preference
One of the biggest benefits of a split king mattress is customization. Since a split king combines two twin XL mattresses, each sleeper can choose a different firmness level. This is especially helpful for couples with different sleeping preferences. A standard king mattress, on the other hand, offers one feel across the entire bed, which may not work if one partner prefers something softer or firmer.
Sleeper Habits
Think about how you and your partner actually sleep. A standard king size bed works better for couples who like to sleep close together or cuddle, since it’s one mattress with no separation in the middle. If you or your partner tend to toss and turn at night, a split king setup offers superior motion isolation; each person sleeps on their own separate mattress, so movement on one side won't disturb the other. That said, the split design can make cuddling a little harder, even though it still provides plenty of space for couples.
Budget
Budget can also play a role when choosing between a split king vs king mattress. A regular king mattress is usually more affordable because you only need one mattress and one set of bedding. A split king bed often costs more since it requires two twin XL mattresses, two fitted sheets, and sometimes an adjustable base, which can increase the overall price.
Accessibility
Standard king beds are more common, which makes it easier to find bed frames, mattress protectors, and sheets. Split king sheets and other accessories are available, but they can be harder to find and may cost more compared to standard king-size options.
If your needs align, go with a king. But if you simply can’t compromise, bridge the divide with a split king.
Explore Split King and King Mattresses from Casper Today
Once you and your partner have settled the split king mattress vs king debate, find your ideal sleep solution with Casper.
Each of our mattresses comes in both standard king and split king sizes, giving you and your partner the freedom to choose the mattress that matches you best. Whether you prefer classic comfort, enhanced support, or maximum coolness, we have the mattress you’ve been dreaming of.
Browse online, or explore your options in person at a Casper Sleep Shop near you.
FAQs
Is a Split King Just Two Twin Mattresses?
A split king is made up of two twin XL mattresses placed side by side. Together, they create the same width and length as a standard king mattress, but each side can have a different firmness or feel.
Why is a Split King More Expensive?
A split king bed is often more expensive because it uses two twin XL mattresses instead of one king mattress. You may also need two fitted sheets and an adjustable base, which can increase the total cost.
What's the Difference Between a Twin Xl and a Split King?
A twin XL mattress is a single mattress that measures 38 inches wide and 80 inches long. A split king combines two twin XL mattresses placed together, creating a king-size bed that still allows each sleeper to customize their side.
What is a Split Queen Mattress?
A split queen mattress is similar to a split king but smaller. It’s made up of two smaller mattresses that fit together to form a queen size bed, often used with adjustable beds or for couples who want separate support on each side.
Are Split King Beds Good for Couples?
Yes, split king beds can be a great option for couples with different sleeping preferences. Each partner can choose their own mattress firmness while still sharing a king size bed, which can improve overall sleep quality.
