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Ready for a mattress upgrade? A king bed just might be the way to go. 16 inches wider than a queen, this size is ideal for couples or families who want to share the bed without crowding one another. When making your final decision, you'll want to consider mattress material, thickness, firmness, and certifications (we’ve included a variety of each). You'll also want to ensure that you have adequate space in your bedroom to fit a mattress of this size.
To find the best picks for your needs, we sent our team of testers top options to use in their very own homes. After sleeping on them every night for 2+ weeks, we had them rank each option on the basis of comfort, value, ease of unboxing, and warranty length. From ultra-luxurious pillow tops to cooling hybrid options, we're confident these mattresses work for a variety of sleepers and needs.
Without further ado, here are the best king mattresses to upgrade your bedroom.
Best Overall: Helix Midnight Luxe Mattress
Material: Memory foam | Thickness: 14 inches | Firmness: Medium | Certifications: Made in the USA | Warranty: 15-year
Balance of soft and firm
No washable cover
Our best overall pick is the Helix Midnight Luxe mattress, a hybrid option with a medium-firm feel. Ideal for side sleepers, our tester found this mattress to strike the perfect balance between softness for sleeping and firmness for support while reading or working. As with other mattresses-in-a-box, it comes rolled in a large box that's delivered to your doorstep.
A common complaint with memory foam is that it’s hot and stuffy and makes it hard to move around. This isn't a problem with a hybrid mattress like the Helix Midnight Luxe. It's constructed with 6 layers of support, including high-density foam and more than 1,000 individual wrapped coils to cradle and support your body. On top, you'll find an ultra-cooling pillow top that helps to absorb excess body heat and add extra comfort.
One feature to note about this mattress is that it has a 14-inch depth, which is higher than some other options. While our tester personally liked this aspect, you'll want to make sure you have sheets with deep enough pockets.
"I am a side sleeper. My husband sleeps on his back. The Midnight LUXE is one of the top-selling mattresses from Helix for couples because it can accommodate different preferences and sleeping positions. We both woke up feeling refreshed."—Katie Begley, Product Tester
Best Cooling: Tuft and Needle Mint Mattress
Material: Memory foam | Thickness:12 inches | Firmness: Medium | Certifications: CertiPUR-US, GREENGUARD Gold Certified | Warranty: 10-year
Both cushioning and supportive
Only one thickness option
2-3 day off-gassing period
Another bed-in-a-box option, the Tuft & Needle Mint King Mattress has additional technology that provides an even cooler night’s sleep. It has extra graphite infused in the cooling layer as well as a removable and washable cover that makes the mattress more breathable.
After testing this mattress every night for three weeks, our tester gave it high marks for both comfort and overall value. She appreciated how adaptable the foam was, simultaneously soft enough for side sleepers and supportive enough for stomach sleepers. The extra edge support is also very helpful, especially if you toss and turn a lot while you sleep. Note that it only comes in a 12-inch thickness option, which might not be ideal for low-profile beds.
"The Mint slept wonderfully cool and offered excellent cushioning. Good cushioning and pressure relief were my other must-haves. I’m a side and stomach sleeper, and my husband is a side and back sleeper—those the main sleeping styles, which the mattress comfortably supported all three."—Stacey Nash, Product Tester
Best Split: Saatva Classic Mattress
Material: Hybrid (memory foam and inner-spring) | Thickness:11.5-inches or 14.5-inches | Firmness: Plush soft, luxury firm, or firm | Certifications: CertiPUR-US | Warranty: 15-year
Two depth options
Three firmness options
A lot of size options
Delivery can be delayed
In-person delivery and setup
The Saatva Classic Mattress is one of the company’s best-selling mattresses due to its consistently good quality and easy delivery. Handmade to order, this luxurious mattress is available in two different depths and three different firmness levels (the 3-inch pillow top is offered in any firmness level). It's available in both split King and split California King options, one of the few mattress companies to offer both.
Our tester gave this mattress high marks for its soft yet supportive feel, which works well for all types of sleepers (particularly side). While the pillow top will start to mold to your body within the first few weeks, this doesn't fully minimize motion transfer—something to note if you're a light sleeper or your bed partner tosses and turns.
It can also take a while to get a confirmed delivery date. This is due to the company providing both delivery and set-up, rather than shipping through the mail as bed-in-a-box companies do. If you prefer this feature, just expect the overall process to take longer.
"After a month, I was fully hooked and all in on the Saatva. It was just as soft and comfortable when I slept on my back as when I slept on my side as if it knew just how to adapt to my varying sleeping positions."—Lindsay Boyers, Product Tester
Best Memory Foam: Casper Original Mattress
Material: Memory foam | Thickness:12 inches | Firmness: Medium | Certifications: Zero VOCs | Warranty: 10-year
Made with no VOCs
Delivered to doorstep
Softer than other medium mattresses
Casper is a well-known player in the mattress-in-a-box market. Their Original Mattress is a medium-firm foam option that becomes softer over time. Unlike other foam options, which can trap heat and affect the overall quality of your sleep, this mattress is designed with a breathable foam that has thousands of perforations for enhanced airflow. The foam is divided into three supportive zones, which adjust to your body's movements for maximum support.
Our tester gave this mattress particularly high marks for its clean look, cloud-like feel, and durable construction. She also appreciated Casper's generous 100-night sleep trial, which lets you return the mattress at any point during the period—no questions asked.
"The mattress is on the softer side but still offers plenty of support. An average-sized adult should expect to sink into it a little bit. We found the mattress was adequately supportive, but if you prefer firmer foam, you may find the Casper to be too soft."—Katie Begley, Product Tester
Best Hybrid: Purple Hybrid 2
Material: Hybrid | Thickness:11 inches | Firmness: Medium | Certifications: Made in the USA | Warranty: 10-year
Gel and spring
Made in the USA
What sets the Purple Mattress apart from others is the proprietary grid pattern in the supportive gel layer. You can purchase a Purple mattress that only includes this technology, but we like the hybrid version for those who still want the support and airflow that comes with an innerspring mattress. The gel layer provides the cushion and the spring layer makes sure that your mattress stays cool and will last for years. Purple mattresses are some of the more expensive options but users rave about their great sleep.
Best Firm: Tuft & Needle Adaptive Foam Mattress
Material: Memory foam | Thickness:10 inches | Firmness: Firm | Certifications: CertiPUR-US, GREENGUARD Gold Certified | Warranty: 10-year
Only two layers
For all the features of the Tuft & Needle Original Adaptive Foam Mattress, it sure has a great price point. At just above $1000, sleepers will enjoy a firm mattress that is made with adaptive foam to provide extra support at needed pressure points. While it only has two layers, the tech in the mattress still makes sure that you get a customized sleep solution. It also has a washable cover that goes over its graphite cooling gel to keep you cool while you sleep.
Best for Side Sleepers: Nectar Gel Memory Foam Mattress + 2 Pillows Included
Material: Memory Foam | Thickness:12 inches | Firmness: Medium-firm | Certifications: CertiPUR-US | Warranty: Lifetime
Minimal motion transfer
Long trial period
Only one thickness option
If you are a side sleeper or toss and turn a lot, the Nectar Memory Foam mattress is a great pick. It has minimal motion transfer, so even if you move around, your partner will not be disturbed. The mattress also falls just a bit beyond medium firmness, with the extra firmness providing the support that you need. Plus, it has a 365-day trial period, meaning that you can literally sleep on it for a full year and still return it if it’s just not right for you.
Best Organic: Avocado Organic Luxury Plush Mattress
Material: Various with coils | Thickness:18 inches | Firmness: Soft | Certifications: GOLS organic certified latex, GREENGUARD Gold Certified, FSC Rainforest Alliance, eco-INSTITUTE, Standard-100 by OEKO-TEX | Warranty: 25-year
3-inch pillow top
Requires coordinated delivery
If you want the ultimate luxury and are willing to spend quite a bit on a high-quality mattress, Avocado has some great choices. We're particularly partial to their Organic Luxury Plush Mattress, which has 21 layers, including organic and natural latex, cotton, wool, silk, mohair, and flax. The price tag is pretty steep (over $5,000 for a King), but it’s a fantastic product for those who have the room in their budget. It does need specialty deep-pocket sheets, which you can purchase from Avocado along with your mattress.
Best Under-$500: Zinus Green Tea Memory Foam King Mattress
Material: Memory foam | Thickness: 6, 8, 10, or 12 inches | Firmness: Firm | Certifications: CertiPUR-US | Warranty: 10-year
No removable cover
This budget-friendly mattress has over 100,000 positive reviews—and its great performance is only eclipsed by an amazing price. For right around $500 for a King, you can choose from four different thicknesses: 6-inches, 8-inches, 10-inches, or 12-inches. The mattress is made of three memory foam layers using green tea, ActivCharcoal, and biofoam. While it doesn’t have as many features as some other more expensive options, like an easily-removable cover, its materials are high-quality and certified CertiPUR-US.
Best Under-$1000: Bear Original Mattress
Material: Memory foam | Thickness:10 inches | Firmness: Firm | Certifications: EcoFlex Fiberglass Free | Warranty: 10-year
Easy delivery and setup
Only one firmness option
The Bear Mattress combines the best of price, performance, and materials. It is a memory foam mattress that takes extra care in making sure that every part is good for the environment and your health. It is on the firmer side, which is particularly good for those with back issues or sleepers who need that extra support. It comes right to your door and can be unrolled on your bed frame or box spring. Bear offers a 100-night trial period so that you can really test it out before committing for good.
Best Air Mattress: SoundAsleep Products Dream Series Air Mattress with ComfortCoil Technology & Internal High Capacity Pump
Material: Memory foam | Thickness:18 inches | Firmness: Medium | Certifications: Soft, medium, or firm depending on quantity of air | Warranty: 1-year
Can be cold
For situations where you need an extra mattress but don’t have room in your space or budget for something permanent, a high-quality air mattress might be the perfect solution. The Dream Series from SoundAsleep is easy to set up and store, as well as comfortable. It has a SureGrip bottom to keep the mattress in place no matter where you put it. The air mattress also has an internal pump so that you don’t need to spend a lot of time or energy manually blowing it up. As with most air mattresses, it can get cold at night so make sure that you have extra blankets on hand.
"When my husband and I slept on it, the mattress stretched a bit, but it retained its shape. We didn’t have to re-inflate. In fact, we even felt the need to deflate it a bit for a softer, cozier feel."—Charlene Petitjean-Barkulis, Product Tester
Our top pick is the Helix Midnight Luxe Mattress for its great value, easy delivery and setup, and ideal firmness level for most sleepers. If you're on a budget, we recommend the Zinus Green Tea Memory Foam Mattress (view at Amazon), which comes in at a surprisingly affordable price for the quality.
How We Tested
Over the course of 2+ weeks, our testers—who are back, side, and stomach sleepers—used these mattresses in their homes, sleeping on them every night. They assessed each option on their ease of unboxing, warranty, comfort, and overall value. We combined these insights with our editors' and writers' independent research to bring you this list.
What to Look for in a King Mattress
Traditional innerspring mattresses are great for those that need support. Most firm mattresses have springs or coils or are a hybrid option. Memory foam tends to be a bit softer, but it can still be a great choice and many companies are using memory foam to provide cushioning where it’s needed.
Mattresses can come in a variety of thicknesses, usually between 10- and 18-inches, with most available in either 12 or 14. Pillow top mattresses are often the thickest since they have extra components. The thickness of your mattress can create a higher bed, which may be more difficult for those with mobility issues to use. You should also consider your sheets when thinking about your mattress thickness. Extra-thick mattresses may need specialty deep-pocket sheets.
Mattresses are classified as soft, medium, or firm, with some mattresses falling in between these labels. Pillow top mattresses are usually softer, while innerspring mattresses tend to be the firmest. Ideal mattress firmness can be a matter of personal preference. It can also be influenced by your lifestyle and physical needs. For example, active individuals often opt for a firmer mattress that provides maximum support.
Most mattress certifications focus on the materials that go into the mattress. The two most commonly seen certifications include CertiPUR-US and GREENGUARD Gold Certification. Both of these certifications show that the materials are free of volatile organic compounds, VOCs, and other chemicals that could harm the environment or result in health problems for the sleeper. You may also look for organic materials if you really want to go to the next eco-friendly level.
You'll want to consider the breathability of your new mattress, especially if you're a hot sleeper. While foam mattresses can be too warm for some people, you can choose one made with open-cell or ventilated foam for better breathability. For added comfort, you can also opt for a mattress with a breathable cover.
Who is best suited to a king mattress?
King mattresses are one of the biggest options for sleeping of all the sizes of mattresses. If you are very tall, a King mattress might be your best option to stay comfortable. King mattresses are also great for couples who share a bed so that each person has adequate room to get restful sleep. Just make sure that you have enough space in your room to fit a King mattress before making this large purchase.
What is the difference between a king and a California king mattress?
A king mattress is 76 inches wide and 80 inches long. A California king mattress is 72 inches wide and 84 inches long. Most people notice the difference in length between the two options more than the difference in width. You might also opt for a split king mattress or a split california king mattress. This provides some more flexibility and ease to actually moving the mattress. Not all companies offer this option, however.
When is the best time to replace or upgrade your existing mattress?
Upgrading your mattress will depend on how much use it gets. Your master bedroom mattress will understandably wear out sooner than an infrequently-used guest room mattress. The important thing to do is make sure to replace your mattress before it breaks down.
“You don’t wait to replace your shoes until your feet hurt. Don’t wait to replace your mattress when your back starts hurting,” says Keith Moneymaker, Owner of Sweet Dreams, a North Carolina-based mattress company.
Why Trust The Spruce?
This article was researched and written by Katie Begley, a freelance writer specializing in home and family products. Katie has been writing for The Spruce since 2019. To make this list, Katie considered how each mattress works for different sleeping styles and needs. She poured over dozens of customer reviews, along with insights from experts and The Spruce's team of testers.