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The 6 Best King-Size Mattresses to Sleep Like Royalty

No need to count sheep! These best king-size mattress picks will have you sleeping like a baby in no time.

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The Best King Size Mattress Picks For A Good Nights SleepRD.COM, VIA MERCHANT (3)

Are you losing precious hours of sleep fretting over the best mattress to buy? We’re here to help. Our guide on how to buy a mattress reveals the ideal time to shop and how to score the best mattress deals. If you have narrowed down your search between king-size and queen-size mattresses and are on the hunt for the best king-size mattress, look no further. Whether you’re searching for the best plush king-size mattress or the best firm king-size mattress, we thoroughly researched the best options for every type of sleeper.

“King-size mattresses are a popular choice for many due to several factors that cater to both individual comfort and overall sleep quality. These factors include more space for couples, comfort for larger individuals and accommodation of various sleeping positions,” explains Dr. Shelby Harris, director of sleep health at Sleepopolis.

Whether snoozing, working or catching up on the newest docuseries, you spend a lot of time in bed. Purchasing the best king-size mattresses for your lifestyle is worth it in the long haul. From the best bed-in-a-box king mattress to the best memory foam king-size mattress, prepare for the good night’s sleep you always deserved.

The best king-size mattresses

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Helix Midnight
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Best overall king-size mattress

Helix Midnight Mattress

While midnight might be Taylor Swift’s hour for creativity, the Helix Midnight mattress offers hours of restful sleep, especially if back pain haunts your dreams. This medium-firm mattress with pressure relief is the best king-size mattress for an array of sleeping positions. It features multiple middle layers that support the body, reducing the chances of night-long tossing.

This best king mattress is made in the U.S. without the use of harmful chemicals, and hot sleepers have the option to add on a GalcioTex cooling cover. It comes with a 10-year warranty, and Helix offers a 100-night sleep trial, so if you don’t fall in love with your new mattress, you can send it back. However, based on our tester’s review of the luxe version of the Helix, we’re pretty sure you’ll think this king-sized mattress is a keeper.

“It’s the feeling of snuggling up to the cool side of the pillow 100% of the time but in mattress form,” according to our tester.


  • Hybrid mattress
  • Ideal for a variety of sleeping positions
  • Mattress construction promotes spinal alignment
  • 100-night trial
  • 10-year warranty
  • Free shipping


  • Pricey

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Nectar Memory Foam
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Best value king-size mattress

Nectar Sleep Memory Foam Mattress

The Nectar Sleep memory foam mattress has an average of 4.7 out of five stars from nearly 53,000 reviews—talk about customer satisfaction! This memory foam mattress contours to your body while keeping you cool and calm. Though not cheap, per se, this is a budget pick as far as quality mattresses go. Plus, a truly good night’s sleep is priceless.

The polyethylene fibers of this best king-size mattress lure heat away from the body, keeping you sweat-free and cozy all night long. The Nectar falls right in the middle of the firmness scale, so it’s not too hard and not too soft—it’s just right. Our deputy shopping editor, Reina Galhea, has been sleeping on the cooling version of this mattress for well over a year now and raves about its comfort.

“My husband and I revel on a daily basis about how comfortable this mattress is. It’s in an entirely different league than our old spring mattress, and we’ll never ever go back,” she says.


  • A bargain compared to other high-quality mattresses
  • Therapeutic gel memory foam layer for pressure relief
  • Designed to keep you cool
  • 365-night trial
  • Forever mattress warranty
  • Free shipping and returns


  • Slight odor after first opening
  • Heavy box

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Dreamcloud Mattress With Dog Ss Edit
Jill Schildhouse for rd.com

Best king-size mattress for back pain

DreamCloud Premier Hybrid Mattress

The DreamCloud Premier Mattress is ideal for people who suffer from back pain. This mattress is constructed to relieve pressure while evenly distributing body weight, reducing the chances of sore spots occurring. It features a buttery-soft cashmere-blend quilted cover and seven layers of memory foam and soft foam designed to cradle the head and body for a stress-free slumber.

This is one of the best king-size mattresses for hot sleepers, too—just ask our tester who has been sleeping on it for more than a year. “We didn’t even realize how unsupportive our previous mattress had been (one of the signs it’s time for a new mattress) until we started waking up with fewer “oofs” and “ouches,” thanks to the DreamCloud. The 2.5 inches of memory foam in the pressure-relief comfort layer had the exact balance between hugging us and flexing as needed,” she writes in her DreamCloud review.


  • Dynamic transition layer for proper spinal alignment
  • Memory foam layer for pressure relief
  • Plush soft foam layer for extra comfort
  • 365-night trial
  • Lifetime warranty
  • Free shipping


  • Pricey

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Rd Editor Tested Saatva Mattress
Madi Koetting/rd.com

Best plush king-size mattress

Saatva Classic Innerspring Mattress

The plush Saatva classic king-size mattress features a 3-inch standard pillow top available in three firmness levels: plush soft, luxury firm and firm. Its dual-coil design, constructed from recycled carbon steel, ensures your mattress won’t be sagging anytime soon. Its plush, body-hugging soft foam has added padding in the pillow top for extra comfort. This mattress is ideal for individuals who find most mattresses too hard and stiff. The Saatva Classic is also a smart choice for side sleepers, as it offers extra contouring.

All Saatva mattresses are American-made and constructed from high-quality, consciously sourced materials. This non-toxic mattress has an organic cotton cover, a botanical antimicrobial treatment and CertiPUR-US-certified foams. There’s also a flame-retardant barrier made from natural thistle pulp, rather than chemical sprays.

Madi Koetting, our products reviews home editor, personally tested the Saatva classic, and says, “My Saatva mattress review taught me I don’t have to sacrifice soft, plushness for a strong, supportive mattress. I also feel confident knowing this mattress is going to last me a very long time. It’s like sleeping in a luxe hotel every night, except it’s my apartment and I never have to check out.”


  • Deep, body-hugging soft foam and extra pillow top padding
  • Free in-room delivery and setup
  • Free mattress and foundation haul-away
  • 365-night trial
  • Lifetime warranty


  • Pricey

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Bear Elite Hybrid Mattress
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Best firm king-size mattress

Bear Elite Hybrid Mattress

Just as Goldilocks has her personal mattress preferences, the Bear Elite hybrid mattress comes in three available firmness options: soft, medium and firm. For folks seeking the best firm king-size mattress, this hybrid mattress is ideal for deep sleepers.  A “cool” fact about this hybrid mattress is that the cover uses a phase-change material that makes it cool to the touch. Hot sleepers will appreciate the breathable Celliant fibers, which keep things chilly all night long. Plus, the copper-infused memory foam whisks away body heat.

A unique zoned coil system conforms to your body’s curves, evenly distributes weight and provides added lumbar support where you need it most. It’s constructed from environmentally friendly materials and CertiPUR-US-certified memory foam, so you can sleep soundly knowing it’s safe for you and the planet.


  • Three available firmness options
  • Copper-infused memory foam with antimicrobial benefits
  • Reinforced edge coils
  • 120-night risk-free trial
  • Lifetime warranty
  • Free shipping


  • Mattress build favors side sleepers

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Nolah Evolution 15 Inches
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Best bed-in-a-box king-size mattress

Nolah Evolution Mattress

The Nolah Evolution hybrid mattress is one of the best king-size mattress-in-a-box options. But don’t let the boxed bed concept fool you: The 15-inch-thick mattress is constructed with seven durable layers and built to last.  The brand’s proprietary foam is infused with billions of microscopic air bubbles to relieve pressure on joints and muscles. Its 8-inch coil support system provides optimal support, structure and stability, and the individually wrapped coils respond to movement and weight distribution, offering superior spinal alignment for just about any sleeping position.

Upon unboxing the mattress, it looks just as cool as it acts. The Nolah Evolution has an organic cotton Euro mattress topper that pulls heat away from the body. There’s also a layer of graphite-infused cooling foam and a breathable border gusset that dissipates excess heat.


  • Designed for side, back and stomach sleepers
  • 15 inches thick with seven layers of high-quality materials
  • 2 inches of high-resilience foam offers complete body support
  • 120-night trial
  • Lifetime warranty
  • Free shipping


  • So thick it may be hard to get fitted sheets to stay on

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What to look for when buying a king-size mattress

When shopping for a king mattress, it is important to consider the size and fit, firmness level, support and pressure relief, materials and construction, edge support, temperature regulation, sleep trial and warranty, budget, individual needs and preferences and partner compatibility,” Harris explains. “These factors will help you choose a mattress that suits your sleep style and comfort levels and provides you with years of restful sleep.”

Consider what type of sleeper you are: back, stomach or side. Next, determine your firmness preference. Mattress firmness rates on a scale from one to 10, with one being the softest and 10 being as firm as it gets. If you like a softer mattress, go for a plush or pillow-top design. If you prefer firm, a memory foam mattress is your best bet. For a middle-of-the-road pick, a hybrid mattress offers the best of both worlds.

It’s always important to stick to your budget and, luckily, you don’t have to spend a fortune. Tons of cheap mattresses offer exceptional value. If you go with an inexpensive pick, consider adding a mattress topper to increase the comfort level and add a layer of protection. Also, invest in a solid mattress protector to extend the lifespan of your king-size mattress.

Types of king-size mattresses

  • Innerspring mattresses: Innerspring mattresses are the most common type of mattress. They’re constructed with a steel coil support system and layers of cushioning material.
  • Memory foam mattresses: Memory foam mattresses are made from supportive foams that contour to your shape. The foam is temperature sensitive, so it softens and conforms to your body when you lie down, and then returns to its original shape when you get up.
  • Latex mattresses: Latex mattresses are made from natural or synthetic latex foam, which is derived from rubber tree sap. Latex mattresses are known for their durability, comfort and support. They’re also hypoallergenic and resistant to dust mites, mold and mildew.
  • Hybrid mattresses: Hybrid mattresses are a combination of two or more types of mattress materials, such as memory foam, latex and innerspring coils. They combine the comfort and support of memory foam with the bounce and responsiveness of innerspring coils.

Why you should trust us

Quality sleep is essential and, as Harris puts it, “A good mattress is important for your overall health and well-being. It can help you achieve deeper, more restorative sleep, which can improve your energy levels, mood, and cognitive function. It can also prevent or alleviate back pain, enhance joint health, support muscle recovery, reduce stress and promote relaxation.” These are the things we kept in mind as we heavily researched the best king-sized mattresses.

How we chose the best king-size mattresses

There are many, many king-size mattresses on the market, so when narrowing them down to the very best, we looked at mattress features, firmness, customer reviews, price and overall value. Plus, we took insight from our editors, who personally tested a couple of the picks. Taking all of that into consideration, we took dozens of options and dwindled the list down to the six best king-size mattresses.


What are the dimensions of a king-size mattress?

A standard king-size mattress size is 76 inches wide and 80 inches long, and a California king-size mattress measures 72 inches wide and 84 inches long.

“A California king is best for taller people who prioritize extra legroom and couples who prefer a narrower mattress with extended length,” Harris says.

What is a split king mattress?

A split king-size mattress is two twin XL mattresses pushed together, each measuring 38 inches wide by 80 inches long.

Harris says, “A split king is best for those with differences in sleep preferences, people with adjustable bed frames and those seeking a customizable mattress.”

About the expert

  • Dr. Shelby Harris is the director of sleep health at Sleepopolis. She’s a licensed clinical psychologist specializing in behavioral sleep medicine, and board certified in Behavioral Sleep Medicine (BSM) by the American Academy of Sleep Medicine.

Katelyn Chef
Katelyn Chef is a writer, home decor enthusiast and eyeglass lover. When she’s not writing about lifestyle, home décor, pets and travel, Katelyn loves photography, creating content for her lifestyle blog, caring for her hydrangeas and drinking iced coffees.