10 Best Firm King Mattress of August 2025

• King size bed in a box: For deep sleep you've always dreamed of, this body contouring memory foam mattress delivers; 12 inch mattress comes compressed and rolled in a box for your convenience
• Sleep soundly: Designed with layers of memory foam for firm support and pressure relief. The support foam core reduces motion transfer for peaceful, undisturbed sleep
• Maintenance free: Made of hypoallergenic material to keep out dust mites, pollen, mold and pet dander—perfect for kids or adults who suffer from allergies
• King size: Measures 75" W x 79" D x 12" H and is compatible with most king bed frames
• Ready for instant enjoyment: Arrives in a box. Simply unbox, cut the protective wrap, unroll and watch the mattress expand. Mattress is safe to sleep on immediately but can take 72+ hours for any risidual odors from packaging to dissipate and for mattress to completely expand based on ambient room temperature, humidity, air pressure & ventilation.

Signature Design by Ashley

• King size bed in a box: For supportive, dreamy sleeping, this mattress brings it home with comfortable layers; Plus, it comes in a box, so it's easier than ever to get a better night's rest
• Hybrid mattress: Mattress is designed with gel memory foam, upholstery grade comfort support foam, and 360 individual power packed wrapped coils for maximum lumbar support. Quilt foam gives you that soft, cozy comfort you crave
• Maintenance free: Made of hypoallergenic material to keep out dust mites, pollen, mold and pet dander—perfect for kids or adults who suffer from allergies.2 perimeter rows of 9 inch 13-gauge pocketed coils
• King size: Measures 76" W x 79.5" D x 12" H and is compatible with most king bed frames
• Ready for instant enjoyment: Arrives in a box. Simply unbox, cut the protective wrap, unroll and watch the mattress expand. Mattress is safe to sleep on immediately but can take 72+ hours for any risidual odors from packaging to dissipate and for mattress to completely expand based on ambient room temperature, humidity, air pressure & ventilation.

Signature Design by Ashley

• FIRM SUPPORT, PLUS MORE - Our firmest mattress ever is engineered with 10% more heavy gauge steel iCoil pocket innersprings for added stability and extra firmness, ideal for stomach sleepers and plus-sized individuals
• SUPPORTIVE FOAM & POCKET SPRINGS - 1.25 inches soft comfort foam, 2.5 total inches durable high-density foam and 7.5 motion-isolating iCoil pocket springs with a microfiber-filled euro top and quilted jacquard cover
• CERTIPUR US CERTIFIED - Highest quality foam is CertiPUR-US Certified for durability, performance, and content
• EXPERTLY PACKAGED - Our technology allows this mattress to be efficiently compressed into one box that’s easily shipped and maneuvered into the bedroom; simply unbox, unroll and this mattress does the rest, expanding to its original shape within 72 hours
• Worry-free 10 year limited warranty included; twin mattress supports a maximum weight of 250 lbs, while all other sizes can support up to 500 lbs
• 1.5 top Comfort Foam layer, 2.5 inch High Density Foam Support layer
• 7.5 inch base layer of over 10% more individually wrapped coils assures no motion transfer
• Extra firm support
• Only the Highest Quality of Foam - Foam is CertiPUR-US Certified for durability, performance, and content
• Worry free 10 year limited warranty

Zinus

• GET UP WITHOUT ANY PAINS- Novilla king size mattress with 4 layers all-foam system, the foam mattress not too soft nor too firm for all sleep positions. This medium firm mattress is made of gel memory foam combined with comfort foam, plus high-density foam underneath, which aligns your spine and evenly disperses your body weight to relieve pressure points while you are sleeping.
• COOLING KING MATTRESS FOR RESTFUL SLEEP- Novilla 10 inch king size mattress is designed with gel-infused memory foam to keep you cool & stay comfortable all night long. Bamboo fabrics in the mattress surface to enhance 30% breath-ability. The middle foam layer is designed as an airflow channel to increase airflow through all areas of this king foam mattress.
• ODORLESS & PLUSH FEEL- Mattresses are made of CertiPUR-US Certified foam, without any harmful off-gassing and substances like formaldehyde, mercury, and other heavy metals. Removable bed mattress cover use skin-friendly rayon cotton fabric, heavenly soft to touch. Novilla king memory foam mattress gives you a healthier and cloud-like experience.
• KING MATTRESS IN A BOX & FITS ALL BED FRAMES- Such fun to receive a mattress that’s rolled and compressed in a box . Follow the instructions and see how the magic happens. It is easy to set up and fits all kinds of king bed frames, even on the floor. Mattress is recommended 72 hours for air out and reshape.
• HASSLE FREE FOR RETURN & REFUND- Mattresses are covered by a 10-year limit warranty and 30-days money-back return policy. With our professional customer care, we help deal with any dissatisfaction problems. You can enjoy this memory foam king mattress without concerns while you are following your dream.

Novilla

• AS COOL AS IT GETS - Settle in to a bed made with our most cooling formula yet, promising perfectly temperature-regulated sleep and a clean feeling night after night, all thanks to our enveloping memory foam packed with cooling gel and green tea
• PRESSURE-RELIEVING FOAMS - 2 inch ultra-cooling gel and green tea infused memory foam, 3 inches soft comfort foam, and 7 total inches durable high density base support foam; ideal for side sleepers and average-weight sleepers
• CERTIPUR US CERTIFIED - Highest quality foam is CertiPUR US Certified for durability, performance, and content
• EXPERTLY PACKAGED - Our technology allows this mattress to be efficiently compressed into one box that’s easily shipped and maneuvered into the bedroom; simply unbox, unroll and this mattress does the rest, expanding to its original shape within 72 hours
• Worry-free 10 year limited warranty included; twin mattress supports a maximum weight of 250 lbs, while all other sizes can support up to 500 lbs

Zinus

• Swiss Ortho Sleep, Most Popular Pocket Encased Coil Spring MATTRESS is a Phenomenal High-Quality 12-Inch Certified Independently & Individually Wrapped Pocketed Encased Coil Pocket Spring Contour MATTRESS. This Swiss Ortho Sleep Mattress is Temperature Sensitive, Body Forming Super Long Lasting High Quality & Extremely Durable, for Many Years of Undisturbed Night's Sleep,
• Each Seperate Pocketed Coil is Individually & Independantly Wrapped to Provide a Support System for an Individualized Comfort by Contouring Precisely to each Person's Body Perfectly. It Also Doesn't Transfer Motion, for a Peaceful Undisturbed Sleep Even if Your Partner Moves at Night.
• Our Signature Motion Isolation Pocketed Encased Coil Mattress is Made for Uptimum Deep Comforting Pressure Relief Sleep. By Relieving The Pressure Points, Pocket Coil Mattresses Allow Blood & Much Needed Oxygen to Circulate & Flow More Efficiently Throughout Our Bodies. This Mattress Also Contains a Bamboo Cover Which Allows Breathability all throughout.
• Swiss Ortho Sleep Always Comes with a 10 Year ,
• It is Delivered to you in an Easy and Convenient Compressed Packing.

Swiss Ortho Sleep

• MEMORY FOAM MATTRESS TOPPER—Designed with the same pressure-relieving TEMPUR material found in our mattresses, this 3 inch memory foam mattress topper conforms to your body to deliver more restful sleep.
• ADAPTS TO YOUR BODY—TEMPUR material responds to your body’s temperature, weight, and shape for precise, personalized comfort and support.
• WASHABLE COVER—Say goodbye to dirt, dust, allergens, and dust-mites with a breathable, machine-washable cover.
• MULTI-USE TOPPER—This conforming mattress topper is not only the perfect way to upgrade your own bed, but also enhances comfort in guest rooms, dorm rooms, for travel, and more.
• DURABLE & RELIABLE—More durable than the average memory foam mattress topper, our innovative, proprietary material is designed for years of long-lasting comfort that won’t let you down.

Tempur-Pedic

• Gorgeous sapphire blue euro pillow top
• Beautifully detailed stretch knit quilted cover optimizes conforming properties
• High-quality memory foam contours to your body for a comforting feel
• Individually wrapped innerspring coils provide orthopedic support and prevent motion disturbance
• Naturally hypoallergenic and resistant to allergens, mold, bacteria, and dust mites and meets CertiPUR-US program standards for performance, emissions, and durability
• Medium-Plush Feel and Adjustable Base Friendly; 10 Year
• Mattress ships compressed, rolled in a box conveniently delivered to your door for easy set-up; frame/foundation/base not included

Vibe

• Composed of 5 layers includes pocket spring
• Memory foam adapt to your body shape and temperature
• Gel infused memory foam regulates temperature while conforming to the body to ease pressure points
• To ensure that this mattress lasts many years, its coils are protected by multi HD and memory foam layers which add to unparalleled quality and incredible comfort.
• 10 year limited Manufacture warranty

Olee Sleep

• THE RIGHT COMBINATION - Our special recipe for rejuvenating rest? Refreshing green tea and moisture-absorbing Activ charcoal infused into pressure-relieving memory foam that cradles your shape so you awake free of aches and pains and fresh as a daisy
• PRESSURE-RELIEVING FOAMS - 3 inches conforming memory foam, 2 inches soft, airflow enhancing comfort foam, and 7 inches durable, high density base support foam; ideal for side sleepers and petite to average weight sleepers
• CERTIPUR US CERTIFIED - Highest quality foam is CertiPUR US Certified for durability, performance, and content
• EXPERTLY PACKAGED - Our technology allows this mattress to be efficiently compressed into one box that’s easily shipped and maneuvered into the bedroom; simply unbox, unroll and this mattress does the rest, expanding to its original shape within 72 hours
• Worry-free 10 year limited warranty included; twin mattress supports a maximum weight of 250 lbs, while all other sizes can support up to 500 pounds

Zinus