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The Best King-Size Mattresses of 2021

A cute puppy lying in bed on its owner's feet
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You’ve unpacked all your boxes and put (almost) everything in its place. It’s time to breathe a sigh of relief and enjoy your new home. Sadly, the old mattress you brought along in the move is keeping you up at night.

Are you considering purchasing a new mattress for your new home? A fresh start is a great time to upgrade your mattress, especially if your new bedroom has more space and you finally have room for a large bed.


But trying to decide on the best king-size mattress available can be overwhelming. And since no two people sleep exactly the same, mattresses tend to differ just as much as personalities. That’s why we’ve researched and compared the best king-size mattresses across a variety of categories:

  1. Best overall mattress: TEMPUR-Adapt Hybrid Mattress by Tempur-Pedic
  2. Best for your budget mattress: The Allswell Mattress by Allswell
  3. Best adjustable mattress: Saatva Classic Mattress
  4. Best memory foam mattress: TEMPUR-ProAdapt mattress by Tempur-Pedic
  5. Best out of the box mattress: The Nectar Mattress by NECTAR
  6. Best cool sleeper mattress: Serta iComfort Mattress
  7. Best side sleeper mattress: Beautyrest Hybrid Mattress

Our research team analyzed mattresses on the following criteria: brand, price, warranty, trial period, materials, delivery, removal of old mattress and shipping costs. In addition, real customer reviews and ratings provided valuable insight in selecting our top seven king-size mattresses of 2021.

The top seven king-size mattresses of 2020

Best overall: TEMPUR-Adapt Hybrid Mattress by Tempur-Pedic

Why it made our list

With 1,000+ premium spring coils and supportive memory foam, Tempur-Pedic mattresses provide the ultimate night’s sleep. It’s made with the same pressure-relieving material that was developed by NASA to absorb the g-force of astronauts during shuttle launches. So, the TEMPUR-Adapt Hybrid provides personalized comfort. If you struggle with allergies, a bonus feature is an antimicrobial treatment that protects this mattress against common allergens such as mold and dust mite dander. Your mattress will arrive in five to seven days with free white glove delivery, including mattress set up and removal of your old mattress. The 90-night trial period provides the opportunity to test if the TEMPUR-Adapt is right for your needs. With a solid 10-year warranty, you’ll have peace of mind on this investment.

TEMPUR-Adapt Hybrid king-size mattress reviews

Tempur-Pedic ranked #1 in customer satisfaction for retail mattresses in 2019 by J.D. Power Mattress Satisfaction Report. Their mattresses are the highest ranked in support, durability, comfort, value for the price paid, customer service, and warranty. With close to 19,000 five-star reviews, it’s easy to understand why we awarded the Tempur-Pedic as the top king-size mattress.

TEMPUR-Adapt Hybrid king-size mattress pre-promotional price: $2,899

Best for your budget: The Allswell Mattress by Allswell

Why it made our list

An affordable king-size mattress doesn’t have to mean it’s cheap in quality! Allswell brand offers the best affordable king-size mattress with a wealth of outstanding purchase points. Allswell’s hybrid foam and coil mattress with added edge support offer sleepers a medium firmness that is both soft and supportive. With their 100-night risk-free trial, you can shop from the comfort of your home and test out the Allswell once unboxed. Take advantage of free ground shipping (in the contiguous U.S.), financing as low as 0%, and a 10-year limited warranty.

Allswell king-size mattress reviews

Many customer reviews note they were initially skeptical about the quality of the mattress they’d receive for such a low price. But once testing out the Allswell, they were pleasantly surprised at the comfort, quality and value delivered.

Allswell king-size mattress pre-promotional price: $465

Best adjustable mattress: Saatva Classic Mattress

Why it made our list

This hybrid innerspring and memory foam mattress is designed to flex with your adjustable base while retaining its comforting support and structure. The Saatva Classics king-size mattress is ideal for people experiencing back or neck pain. Customers can try out mattress support with Saatva’s 120-night risk-free trial. Order with ease online, then receive free white-glove delivery, set up, and mattress removal. Financing offers include 0% APR for six months if paid in full.

Saatva Classics king-size mattress reviews

Saatva is one of America’s best-reviewed online luxury mattress brands with an average rating of 9.7/10 on over 40,000 reviews. Rated as “excellent” on Trustpilot, customers who purchased a Saatva mattress praise both the mattress quality and customer service satisfaction.

Saatva Classics king-size 11.5” mattress pre-promotional price: $1,699

Best memory foam: TEMPUR-ProAdapt mattress by Tempur-Pedic

Why it made our list

Memory foam mattresses are made to conform to your body, providing personalized comfort and support. The TEMPUR-ProAdapt mattress is a medium feel with a temperature-regulating SmartClimate dual cover system. Tempur-Pedic provides a 90-night trial, free mattress set up and removal of your old mattress, and a 10-year warranty.

TEMPUR-ProAdapt king-size mattress reviews

Tempur-Pedic is ranked #1 in customer satisfaction with retail mattresses in 2019 by J.D. Power Mattress Satisfaction Report. Customers loved the all-over body support with a lack of uncomfortable pressure points.

TEMPUR-ProAdapt king-size mattress pre-promotional price: $3,699

Best out of the box mattress: The Nectar Mattress by NECTAR

Why it made our list

Mattresses in a box have come a long way. Nectar’s medium-firm foam mattress with a removable Tencel cooling cover unboxes easily. What’s most impressive? The 365-night risk-free trial and forever warranty. Order online or test the Nectar in-store (at 1,500 retailers nationwide). Nectar offers as low as 0% APR financing.

Nectar mattress king-size mattress reviews

Ranked as 2019’s Best Mattress In a Box by USA Today, Nectar’s mattresses come with many accolades, including an overall of 4.7 stars with 30,000+ reviews.

Nectar king-size mattress pre-promotional price: $1,398

Best cool sleeper: Serta iComfort Mattress

Why it made our list

If you sleep hot, a temperature-regulating mattress will help keep you cool and dry. The Serta iComfort mattress is made of foam with a removable Tencel cooling cover. Test this medium firmness mattress in one of Serta’s 1,500 retailers nationwide or order online. Either way, you’ll receive a 10-year limited warranty, free shipping and returns, along with financing options as low as $150 per month. Serta’s 120-day in-home trial gives you the perfect opportunity to decide if this is the right cooling sleeper for you.

Serta iComfort king-size mattress reviews

Serta’s customers who sleep hot rate the iComfort as keeping them cool throughout the night.

Serta iComfort king-size mattress pre-promotional price: $1,699

Best side sleeper: Beautyrest Hybrid Mattress

Why it made our list

Beautyrest’s hybrid mattress with gel, memory foam, and firm pocketed coils is designed to help side sleepers find their perfect sleep position. Beautyrest offers a 100-night in-home trial, free shipping, complimentary white glove delivery, and a 10-year warranty.

Beautyrest Hybrid king-size mattress reviews

Beautyrest was ranked #3 in 2019 by J.D. Power Mattress Satisfaction Report. Side sleeper reviews of Beautyrest note sleeping sounder and waking without aches or discomfort.

Beautyrest Hybrid king-size mattress pre-promotional price: $1,699

*Pricing as of 06/05/2020

Things to consider when shopping for mattresses

Before you start your search for the best king mattress, it’s essential to create a list of your “must-haves” and details needed. Armed with this knowledge, you’ll be able to make an educated decision and not succumb to a pressure purchase.

  • What type of mattress works best for your sleep style?
  • Is there a trial period?
  • Is there a return policy?
  • What is the warranty?
  • Is there a delivery and set up fee?

The bottom line

With so many options, finding a new mattress can be overwhelming. Take advantage of the in-home trial and give your new mattress a test run. This will allow you to make an educated decision on what mattress helps drift you off to dreamland.

Frequently asked questions

How much is a king-size mattress? 

Mattress pricing varies based on brand and features. Expect to pay between $400 and $1,000 for an out-of-the-box mattress. Traditional king-size mattresses can cost between $900 and $3,000.

What is the best king-size mattress? 

After conducting thorough research, we ranked TEMPUR-Adapt Hybrid Mattress by Tempur-Pedic as Best Overall mattress.

What size mattress should I purchase? 

Take into consideration your overall room size, number of sleepers, and budget when determining what size mattress you should purchase.

Where can I find actual customer mattress reviews? 

When trying to choose the best king-size mattress for your needs, reading other customer reviews can be very helpful. J.D. Power and Consumer Affairs are two trustworthy sites to check out.

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