Limited Time: Up to 25% off sitewide
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Limited Time: Up to 25% off sitewide
800.588.5720
Limited Time: Up to 25% off sitewide

King Mattresses

One of the largest mattress sizes on the market, king size mattresses measure 76” wide by 80” long. BedInABox® king size mattresses provide plenty of bed for anyone who needs more sleeping space.

Essential Product Image
9” multilayer foam construction built with our CoolRest® Gel memory foam for any sleeper who wants simple, long-lasting support.
Firmness: Medium-firm
King $749.25 $999
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Original Product Image
11” multilayer foam construction designed with CoolRest® Gel memory foam to bring you cool, comfortable memory foam support.
Firmness: Medium-firm
King $944.25 $1,259
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Azul® Product Image
11” medium-soft multilayer foam construction with an UltraCool® soft knit cover and our most advanced cooling system to keep you sleeping comfortably.
Firmness: Medium-soft
King $1,176.75 $1,569
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Original Hybrid Product Image
11" of our classic CoolRest® Gel memory foam construction, enhanced with spring support for added lift.
Firmness: Medium-firm
King $1,101.75 $1,469
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Tranquillium® Product Image
12” and three layers of memory foam support infused with CoolRest® technology for those seeking maximum support and comfort.
Firmness: Firm
King $1,334.25 $1,779
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BedInABox® Dual Hybrid® Product Image
13” of premium foam and spring support with the highest coil count in the industry. Advanced pressure relief exactly where you need it.
Firmness: Medium-firm
King $2,046.75 $2,729
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Eco-Lux® Product Image
11" of plush memory foam made with renewable materials. Features a breathable, moisture wicking organic cotton cover.
Firmness: Medium-firm
King $1,574.25 $2,099
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How big is a king size mattress?

A standard king size mattress is 76 inches wide by 80 inches long.

Mattress Size Chart

Who should sleep on a king mattress?

Couples & Families Couples & Families

King mattresses give couples plenty of sleeping space, often enough for the kids or pets to climb in, too.

Teens & Young Adults Primary Bedrooms

The king size bed is perfect for most primary bedrooms with 16 more inches of elbow room than the queen size.

Quality comfort, risk-free

Try your king mattress in a box risk-free for 120 nights. If you don’t love your new BedInABox® after sleeping on it for 60 nights, let us know and we will get the return process started. Details can be found in our Return Policy.

120-night free trial
safe, supportive memory foam

Certified king-size support

All of the memory foam we develop for our king size memory foam mattresses is CertiPUR-US® certified. This means that the foam has been tested by accredited labs and has been certified as safe to sleep on. We use multiple layers of our house-made memory foam to provide the perfect balance of support and pressure relief, for all sleepers.

Sleep now, pay later

We partner with Affirm to offer flexible financing options, so you can pay with fixed monthly payments with rates between 0-30% APR. Simply select Affirm at checkout and complete an application that won’t affect your credit score. Prequalify Now.

sleep now, pay later

Buying a Foundation for a King Size Bed

Create a more supportive sleeping experience by pairing your king size mattress with a king size foundation. A mattress foundation serves as a base for your mattress and generally uses solid planks or slats to support and lift your mattress off the ground. There are different types of foundations suited to different mattresses and sleep preferences, BedInABox® currently offering three options compatible with a king mattress: a slatted foundation, a platform foundation and an adjustable foundation.

Clever Connect™

Provides simple, slatted support for memory foam or hybrid mattresses. This sturdy foundation is available in a 5” profile or an 8” profile and can be paired with optional foundation legs for additional height.


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Clever Connect™
Platform BedInABox®

Platform BedInABox®

Best described as a combination of a standard mattress foundation and a decorative bed frame, our upholstered platform offers a slightly lower profile than pairing a solid foundation with a separate bed frame and is compatible with all BedInABox® mattresses.


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MotionInABox™ Adjustable Beds

Solid mattress bases that can be raised or lowered to create a custom sleep experience. The MotionInABox™ adjustable bases are available in two different models, MotionInABox™ 1.0 and MotionInABox™ 2.0, both in the Split King size compatible with standard king size mattresses.


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MotionInABox™ Adjustable Beds
 

Which King Size BedInABox® is right for you?

Essential Product Image
Essential

Our 9” Essential mattress is a simpler take on our Original Mattress, utilizing the same dual layer memory foam technology in a slightly thinner, medium-firm mattress profile.

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Original Product Image
Original

The Original mattress is our classic 11” dual-layer memory foam mattress. The two layers combine plush, temperature regulating comfort and medium-firm support to provide the perfect level of contouring alignment.

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Azul® Product Image
Azul®

The Azul® mattress features 11” of cooling comfort. The dual layer medium-soft mattress tops multiple layers of phase change material with an UltraCool® soft knit cover to offer our most advanced cooling system.

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Original Hybrid Product Image
Original Hybrid

11" of our classic CoolRest® Gel memory foam construction, enhanced with spring support for added lift.

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Tranquillium® Product Image
Tranquillium®

The Tranquillium® mattress is built with 12” and three layers of firm memory foam to maximize support without sacrificing comfort.

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BedInABox® Dual Hybrid® Product Image
BedInABox® Dual Hybrid®

The Dual Hybrid® mattress is 13” of premium comfort, combining the support of memory foam and springs. The BedInABox® hybrid mattress features the highest coil count in the industry to provide ultimate lift, support and pressure relief exactly where you need it.

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Eco-Lux® Product Image
Eco-Lux®

The Eco-Lux mattress is made with 11" of renewable memory foam, topped with a naturally moisture wicking organic cotton cover. The only Bio-Preferred® mattress on the market and our most sustainable sleep solution.

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Find your king size mattress


Made in the USA with the most premium foams and materials, all of our King mattresses are backed by a 20-year limited warranty so you can rest easy, night after night.


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Find your king size mattress


Made in the USA with the most premium foams and materials, all of our King mattresses are backed by a 20-year limited warranty so you can rest easy, night after night.


Shop Mattresses

Frequently Asked Questions

What is the standard size of a king mattress?

What is the difference between a queen and a king mattress?

A king mattress is 16 inches wider than a queen mattress, but the two sizes share a length of 80 inches. A king measures 76” wide by 80” long and a queen measures 60” wide by 80” long.

How many BedInABox® mattresses come in the King size?

All six BedInABox® mattresses come in the King size option.

What size room fits a king size mattress?

As one of the largest mattress sizes on the market, a king size mattress generally requires around 145 square feet of bedroom space to comfortably accommodate the king bed and other furniture.

Is a King mattress the same size as two Twin XL mattresses?

The width and length of the standard king mattress size is the same as the width and length of two twin XL mattresses side-by-side. The twin XL mattress setup is beneficial for couples with different sleep preferences, especially if they utilize a split king or twin XL adjustable base sleep system.
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Find your perfect mattress in a box

Compare the industry-leading quality, comfort & support of BedInABox® memory foam mattresses to some of our biggest competitors in the sleep business.

Compare Mattresses