King vs. Split King — What’s the Difference?

For most couples, king size beds are pretty great. They’re roomy enough that everyone has plenty of personal space, and they also fill out master bedrooms in a way full and queen size mattresses just don’t. But did you know there’s another option that allows you to have all the legroom of a king size bed and still get all the personalization of your own twin XL bed? It’s called the split king.

Split kings are great for a lot of reasons. They let couples choose different mattress materials, different firmness levels, and different base options. If you’ve got wildly different preferences as a couple, a split king may be the only way two sleepers can share a bed. Let’s talk about the differences between a king and a split king and how each mattress size might be right for you.

Standard King Size Mattress

At 76 inches long and 80 inches wide, the standard or eastern king is one of the most popular mattress sizes for couples. And a traditional king size mattress, unlike a split king, is just one mattress with the same base underneath it. It gives you plenty of room to spread out and roll around in your sleep, and it’s really the only bed size that offers the same amount of width you’d get on a twin bed. Full and queen mattresses don’t even come close.

Pros and Cons of a King Mattress

While the regular king’s biggest con is it doesn’t give you the same personalization ability as a split king, this setup does have some advantages.

Pros

• No seam or gap in the middle
• Sometimes less expensive
• Single mattress won’t slide apart like some dual mattresses will

Cons

• Forces couples to use the same firmness level and material
• Won’t accommodate split adjustable bases
• Heavy, cumbersome, and difficult to move

Standard King Mattress Cost

There’s no way around it: a quality king mattress is expensive (not to mention all its accessories). You can pay upwards of $4,000 to $5,000 for a king mattress with a bunch of sleep technologies. Even if you don’t get all the bells and whistles, you still should expect to pay no less than $1,000 for a quality king mattress. Any less, and you’re probably not getting a good-quality product.

The best king mattress on the market is the Zoma Hybrid, a cooling bed built for pain relief. Zoma designed this bed with athletes in mind, so not only does the bed help you sleep deeper, but it enhances muscle recovery and physical performance. You’ll wake up feeling restored every morning with the Zoma Hybrid!

Inside the Zoma Hybrid is a gel-infused foam comfort layer. This cushiony gel layer relieves pressure points and pain without getting overly hot or causing you to sink into your bed.

Next is Zoma’s proprietary Reactiv™ transition foam. Similar to latex, Reactiv™ foam is flexible and buoyant, ensuring you’re well-supported while sleeping. Its rapid responsiveness makes switching positions and getting into bed less laborious in the middle of the night.

At the base of the Zoma Hybrid are a layer of pocketed coils and a foam base. The coils are crucial for supporting your spine and minimizing motion transfer. The foam beneath the coils prevents sagging, lumps, and soft spots to maximize your bed’s longevity.

With the Zoma Hybrid, you score free shipping and returns, a 100-night sleep trial, and a 10-year warranty.

Split King Size Mattress

The split king bed does exactly what its name says: it splits a king right down the center, using two twin XL size mattresses in a regular king size bed frame. There are tons of advantages to the split mattress setup, especially for couples with divergent personal preferences.

For one thing, split kings allow couples to keep to their own preferences and firmness levels. So if one of you wants a medium-firm coil mattress and the other wants a soft latex mattress, there’s nothing stopping you from having both. Another thing is the split king allows partners to have different adjustable bed frames, letting you sleep at the angle you prefer without forcing it on your significant other.

Pros and Cons of a Split King Mattress

Pros

• Offers different firmness and material options to couples
• Much easier to disassemble and move
• Will accommodate dual adjustable bases
• Separate mattresses almost eliminate motion transfer

Cons

• Seam in between mattresses might cause gaps and feel annoying to some sleepers
• Can sometimes cost more than regular king
• Mattresses might start sliding around after a while

Split King Mattress Cost

Split kings can cost more or less than a regular king, depending on the setup and the type of twin XL mattresses you buy. Two twin XL size mattresses can cost anywhere from $300 apiece to $3,000 apiece, giving a regular king mattress a run for its money.

When you factor in having to buy two of everything else: split king sheet sets, two bases, etc., all that can add up pretty quickly. See our guide on twin XL vs split king mattresses.

A popular split king mattress is the Amerisleep AS5, a luxuriously soft bed with a cloud-like feel. Split king mattresses are made with couples in mind and the AS5 is perfect for couples who side sleep, deal with joint pain, or just want an extra-plush bed! The split king pairs with any split adjustable base so couples can alter their side of the bed’s angle as they please.

Inside the AS5 is Amerisleep’s patented Bio-Pur® memory foam. It’s made with castor oil, resulting in a longer-lasting, more breathable, and springier bed compared to other memory foam beds. The Bio-Pur® is pressure-relieving and soft, but won’t leave you feeling unable to move in bed.

Most soft mattresses end up feeling unsupportive, but not the AS5. Amerisleep adds Active Flex foam to the AS5, a springy material designed to enhance the bed’s support. It doesn’t make your bed feel firmer, either, so you still enjoy the bed’s unique plushness.

At the base of the AS5 is Bio-Core® foam. This durable layer supports your spine and back but also the mattress itself. The Bio-Core® base ensures your bed lasts for years without sagging or getting lumpy.

The Amerisleep AS5 comes with free shipping, free returns, a 100-night guarantee, and a 20-year warranty.

FAQs

Do split kings and regular kings require different room dimensions?

The king and split king bed sizes need equivalent room dimensions. They’re both 76 by 80 inches, meaning when you add in the space taken up by whatever bed frame size you get, you’ll still wind up needing a room of around 10 by 9 or more feet to get the requisite 2 feet of space around 3 sides of the bed. If you want to add furniture, 10 by 12 or 12 by 12 feet is probably better to avoid a cramped look.

Do I need two bases for the two mattresses in a split king?

Maybe. A lot of times, even a regular king mattress has two box springs or two mattress foundations under it because king size bed bases can be nearly impossible to move. However, you don’t necessarily have to put your two twin XL mattresses on two different bases. For example, you could lay them both on a king sized platform bed.

But if you want different angles on your adjustable base, you have no choice but to use two.

What bed sheets are best for a split king?

Usually, two sets of twin XL bed sheets work best as split king sheets. If you’re not going to use two separate adjustable bases, you may be able to purchase two separate twin XL fitted sheets and a single flat sheet and quilt/comforter/duvet/etc. However, those who plan to sleep with different adjustments may need to separate everything from the top sheets to the blankets.

What are the benefits of dual adjustable bases?

Adjustable bases have a lot of benefits for some people, and they’re really annoying to others, so two twin XL adjustable bases can offer the best of both worlds to individuals with different sleeping preferences.

Adjustable bases give back pain sufferers and snorers some relief by propping them upright to reduce stress on the spine and blockage in the airways. The two dual bases of the split king will offer this relief to the person who wants it while still allowing the partner who wants to lie flat to do so.

How do I keep split king mattresses from sliding apart?

If you have a bed frame that the mattresses sit on top of rather than inside, the two mattresses of a split king might start to wiggle away from each other. There are several ways to prevent this. First off, non-slip mattress pads between the base and mattresses are almost always a good idea because they can help keep the mattresses from sliding around on top of the base.

A lot of split kings also come with iron plate connectors to help hold the mattresses in place. Adjusting the settings on this connector might just do the trick. Another option is a bed link strap that can help keep your mattresses linked together. If all else fails, a fitted bed frame with rails that come all the way up to the point they surround the actual mattress might be the best solution.

Bottom Line

Both the split king and regular king have their pros and cons, and each one can be an excellent mattress for couples and complete a master bedroom.

However, if one of you really wants a firm mattress while the other prefers a soft one, or if you just can’t agree on whether to get an innerspring or memory foam mattress, a split king is probably your best option. It can help you both fulfill your different sleep needs, keep the conflict to a minimum, and continue to share a bed without sacrificing either comfort or sleep quality.