Best 9-Inch King-Size Mattresses


Our review process

No more spending hours trying to find out which 9-inch king-size mattress to get! By reading this guide, you'll have an excellent grasp on what kinds of mattresses are available on the market, so you can confidently purchase a mattress that will ensure comfortable sleep for years to come.

Here's what we think you'll want to know before buying a 9-inch king-size mattress. These mattresses are perfect for couples, offering extra space for you to spread out. They measure 76" X 80" and are ideal for master bedrooms. However, they are large and heavy, making them difficult to move and flip. Also, they are not suitable for spaces with limited room, making small areas look somewhat cluttered.

9-inch mattresses are less likely to cave in, so the surface will remain flat to ensure adequate support over time. They have a standard thickness, so you can rest assured knowing that they'll be able to fit in nearly all bed frames. However, they provide less support than other types of mattresses, negatively affecting the quality of your sleep. Additionally, they tend to wear out quickly, so they won't last long before beginning to deteriorate.

Our Top Ranking Mattresses:
Our Top Ranking Mattresses
Customer Rating
Brand
Comfort Dreams
Type
memory foam
Comfort
Customer Rating
Brand
Englander
Type
memory foam
Comfort
Customer Rating
Brand
Continental Sleep
Type
pocketed coil
Comfort
medium firm
Customer Rating
Brand
Spring Coil
Type
innerspring
Comfort
medium firm
Customer Rating
Brand
Spring Coil
Type
memory foam
Comfort
medium firm
Best Overall Score
An image of Comfort Dreams M-092513541 Memory Foam King-Size NASA Designed 9-Inch Mattress

For a better night's rest and ultimate comfort, choose a Comfort Dreams Memory Foam King-Size Mattress. This Comfort Dreams mattress features a 9-inch thickness, which doesn't provide the most support. It is available in a king-size, so you are able to stretch out in your sleep. It is dust mite resistant, making it a good choice for those who suffer from allergies.

Featuring a memory foam construction, this Comfort Dreams mattress re-contours itself to your body as you move around at night. It minimizes motion transfer so that you won't be woken up by movement. It has antimicrobial benefits, providing you with a clean and hygienic sleep environment. It is designed with NASA designed foam. It is suitable to use for standard box springs and platform beds.

    Pros
    • Features antimicrobial fabric, preventing mold, bacteria, and dust mites from growing and multiplying
    • Minimizes motion transfer, making it great for restless sleepers
    • Provides pressure point relief, allowing certain areas that are exhausted throughout the day to get the support they need during a night's sleep
    Cons
    • King-size can be difficult to move
    • 9-inch thickness provides less support than thicker mattresses
    • Memory foam construction releases a strong odor
Runner Up
An image of Englander Azalea7522KM Memory Foam King-Size Foam Base 9-Inch Mattress

For a better night's rest and ultimate comfort, choose an Englander Memory Foam King-Size Mattress. This Englander mattress features a 9-inch thickness, so the mattress will not dip in the center or collapse on the sides. It has increased durability, which allows it to remain in excellent shape for years ahead. This Englander mattress is available in a king-size, so you have a lot of space to sleep comfortably.

This Englander mattress has a memory foam construction, which will let you move around in your sleep and then re-contours to your body after you've found a comfortable position. It is built with a foam base, so all dominant pressure areas are adequately supported. It provides pressure point relief so that your spine and joints are well supported to diminish any discomfort. It has a moisture barrier, which helps prevent moisture build-up.

    Pros
    • Foam base supports each part of your body
    • Offers pressure point relief, providing therapeutic benefits
    • Moisture barrier decreases wetness build-up
    Cons
    • King-size does not fit in small rooms
    • 9-inch thickness wears out faster than other thicker mattresses
    • Memory foam construction releases VOCs
Additional Picks
An image of Continental Sleep 900K-1 Medium Firm Pocketed Coil King-Size 9-Inch Mattress

For optimal comfort and a restful night's sleep, consider the Continental Sleep Medium Firm Pocketed Coil King-Size Mattress. This Continental Sleep mattress has a supportive design, aligning your spine horizontally when sleeping on your side. Made to conform to your body, it can help ease pressure and pain in sensitive parts of the body. Featuring a pocketed-coil construction, it gives optimal comfort because it minimizes pressure points. Available in a king-size, this Continental Sleep mattress offers an ample amount of room to stretch out and relax. It features a 9-inch thickness, stopping your mattress from sagging in the middle or falling around the edges. With a medium firm mattress, it requires bones to absorb the most pressure so there is less weight on muscles.

    Pros
    • Medium firm mattress keeps you comfortable and aligned all night long
    • Made to conform to your body for superior pressure point relief
    • Supportive design ensures proper spinal support and alignment
    Cons
    • King-size can be difficult to move
    • Medium firm mattress can put uncomfortable pressure on pressure points
    • 9-inch thickness doesn't provide the best support
An image of Spring Coil Medium Firm Innerspring King-Size 9-Inch Mattress

For a good night's sleep and endless comfort, select a Spring Coil Medium Firm Innerspring King-Size Mattress. This Spring Coil mattress is available in a king-size, so you are able to stretch out in your sleep. It has a 9-inch thickness, so the mattress will not dip in the center or fall on the sides. With a medium firm comfort level, it provides additional support to prevent aches and pains. It provides pressure point relief for added spinal and joint support. It has an innerspring construction, which is able to support numerous sleepers, including stomach sleepers. This Spring Coil mattress is fire resistant, which is a safe choice for your bedroom.

    Pros
    • Medium firm mattress provides the support necessary to keep your body straight
    • Pressure point relief technology ensures that your spine and joints are equally supported in order to diminish any discomfort
    • Comes rolled, making it easy to place your mattress on the bed of your choice
    Cons
    • King-size can be difficult to move
    • Medium firm mattress can put painful pressure on pressure points
    • 9-inch thickness provides less support than thicker mattresses
An image of Spring Coil 7009BW-6/6 Medium Firm Memory Foam King-Size 9-Inch Mattress

Are you looking for a mattress that will give you better support for both your upper and lower body? Read on to learn about the Spring Coil Medium Firm Memory Foam King-Size Mattress. Built with durable materials, this Spring Coil mattress will stay in excellent condition for years to come. With a 9-inch thickness, it provides you with a sturdy sleeping surface that won't sag over time. It has a medium firm comfort, so your back won't collapse, making it easier to breathe while you sleep. This Spring Coil mattress is available in a king-size, so you can have as much space as possible.

This Spring Coil mattress is designed with a soft cover and has a zippered cover, making it easy to place on and take off your mattress. It features a memory foam construction, allowing you to toss and turn and then re-contours to your body after you've settled. Featuring three layers, it creates a secure support system for your entire body. This Spring Coil mattress has a supportive design, which ensures proper spinal support and alignment.

    Pros
    • Medium firm mattress keeps your body comfortable and aligned throughout the night
    • Supportive design ensures proper spinal support and alignment
    • King-size is perfect for big rooms with a lot of space
    Cons
    • King-size does not fit in small rooms
    • Medium firm mattress can put uncomfortable pressure on pressure points
    • 9-inch thickness provides less support than thicker mattresses
An image of NuForm Medium Firm Pocketed Coil King-Size 9-Inch Mattress

For a better night's rest and ultimate comfort, opt for a NuForm Medium Firm Pocketed Coil King-Size Mattress. This NuForm mattress features a pocketed-coil construction, reducing any disturbances from your partner's movement. It is available in a king-size, so you have maximum space to sleep comfortably. This NuForm mattress has a 9-inch thickness, which doesn't provide the most support. It is single-layered and features a medium firm comfort level, providing the support necessary for spinal alignment.

    Pros
    • Medium firm mattress will conform to the natural curves of your spine to keep your body properly aligned
    • Comes rolled to make it easy to transport
    • Features a vacuum packed design, making it easy to transport it into the room you'd like
    Cons
    • King-size does not fit in small rooms
    • Medium firm mattress can put uncomfortable pressure on pressure points
    • 9-inch thickness provides less support than thicker mattresses
An image of Comfort Dreams Medium Plush Gel Memory Foam King-Size 9-Inch Mattress

Looking for a green and eco-friendly mattress? Consider the Comfort Dreams Medium Plush Gel Memory Foam King-Size Mattress. This Comfort Dreams mattress features a 9-inch thickness, which can withstand heavy weight without sagging. It features a medium plush comfort level, which delivers the perfect mix of softness and firmness. With resistance to dust mites, it makes it an ideal choice for people suffering from allergies. Available in a king-size, it ensures that you'll have a lot of space to spread out and have a good night's sleep.

This Comfort Dreams mattress has a removable cover, so you can easily change and clean it. It has a stretch knit cover, keeping your mattress looking newer for longer. Designed with a gel memory foam construction, it features better airflow, which carries heat away from the body. It minimizes motion transfer, which makes it ideal for restless sleepers since any movement remains isolated. With antimicrobial benefits, it fights against any unsafe mold. It is designed with eco-friendly materials, making them resistant to mold and other bacteria and pests.

    Pros
    • Medium plush mattress delivers the ideal mix of softness and firmness
    • Antimicrobial benefits provide a healthier sleep space
    • Eliminates motion transfer, making it great for light sleepers
    Cons
    • King-size does not fit in small spaces
    • Medium plush mattress can get lumpy or sag over time
    • 9-inch thickness doesn't provide the most support
An image of Dreamfoam Bedding Soft Memory Foam King-Size Responsive 9-Inch Mattress

For a better night's sleep and endless comfort, opt for a Dreamfoam Bedding Soft Memory Foam King-Size Mattress. With exceptional breathability, this Dreamfoam Bedding mattress prevents material degradation that would otherwise be caused by moisture and heat. It features a memory foam construction, allowing you to move around in your sleep and then re-contours to your body after you've found a comfortable position. It includes three layers and features a soft comfort level, which is perfect for people who sleep on their side as it better cushions the hips and shoulders. It features a 9-inch thickness, so the mattress will not dip in the center or collapse on the sides. Available in a king-size, this Dreamfoam Bedding mattress offers an ample amount of room to spread out and relax. It has a responsive foam core, meaning it adjusts to subtle movements, allowing it to contour to your body for optimal support. This Dreamfoam Bedding mattress features a soft cover, providing an added layer of comfort and protection to your mattress. Made without PBDEs, TDCPP, or TCEP, it eliminates the danger of these unnatural compounds.

    Pros
    • Soft mattress for exceptional support, especially for people who sleep on their side
    • Responsive foam core reacts to subtle movements, allowing it to contour to your body for optimal support
    • Breathable construction promotes air flow to prevent mildew and dust mites from developing
    Cons
    • King-size can be difficult to move
    • 9-inch thickness provides less support than thicker mattresses
    • Memory foam construction releases a strong odor
An image of Dreamfoam Bedding Medium Firm Memory Foam King-Size Foam Base 9-Inch Mattress

For a better night's rest and endless comfort, choose a Dreamfoam Bedding Medium Firm Memory Foam King-Size Mattress. This Dreamfoam Bedding mattress offers pressure point relief, making it ideal for stomach sleepers. It has a memory foam construction, allowing you to move around in your sleep and then re-contours to your body after you've settled. With a 9-inch thickness, this Dreamfoam Bedding mattress provides you with a sturdy sleeping surface that won't sag over time. It includes three layers and features a medium firm comfort level, providing overall support of your body for deep and restful sleep. Available in a king-size, this Dreamfoam Bedding mattress ensures that you'll have lots of space to spread out and sleep comfortably. It has a foam base, ensuring all major pressure points are well supported. Made without PBDEs, TDCPP, or TCEP, it eliminates the risk of these hazardous chemicals.

    Pros
    • Medium firm mattress provides a comfort level suitable for anyone searching for the perfect mix of softness and support
    • Foam base supports each part of the body evenly and individually by spreading your weight across the mattress
    • Offers pressure point relief, decreasing pain or stiffness while sleeping
    Cons
    • King-size can be difficult to move
    • Medium firm mattress can put uncomfortable pressure on pressure points
    • 9-inch thickness provides less support than thicker mattresses
An image of Dream Solutions USA Firm Innerspring King-Size Firm Poly Foam 9-Inch Mattress

For a better night's sleep and endless comfort, choose a Dream Solutions USA Firm Innerspring King-Size Mattress. This orthopedic mattress comes with a no-flip construction, eliminating the hassle that accompanies having to flip heavy mattresses. It has a supportive design, aligning your spine horizontally when sleeping on your side. Featuring an innerspring construction, this orthopedic mattress adjusts easily to your body.

Available in a king-size, this orthopedic mattress will provide maximum bed space. It features a firm comfort level, providing support to the lumbar region in any sleeping position. It has a 9-inch thickness, so your mattress will not dip in the center or fall around the edges. This orthopedic mattress features a quilted cover, providing added comfort and cushioning. Built with a VertiCoil innerspring core, it has a more durable perimeter and excellent orthopedic support. Featuring a firm poly foam core, it provides exceptional support by filling empty gaps between your body and the mattress.

    Pros
    • Firm mattress will conform to the natural curves of your spine in order to keep your body properly aligned
    • Built with a firm poly foam core to prevent sagging and soft spots
    • Features a VertiCoil innerspring core, providing more support around the perimeter and edges of the mattress
    Cons
    • King-size can be difficult to move
    • Firm mattress can put uncomfortable pressure on pressure points
    • 9-inch thickness doesn't provide the best support
Need Help Narrowing Down Your Options? Here's Some Additional Information to Know:
Mattress Type: Which Is the Best Choice for You?
Gel Memory Foam Mattresses

Trying to find a good gel memory foam mattress? This 9-inch king-size mattress might be a good choice. These breathable gel memory foam mattresses will provide proper airflow and ventilation to prevent moisture build-up. With even weight distribution, they will support your weight. They are made from various materials, so you can choose from a range of levels of comfort and foam densities. These mattresses come with pressure-point relief, which helps alleviate any stress in your joints. Thanks to superior motion isolation, they are perfect for couples with an active sleeper.

Memory Foam Mattresses

Before you buy, you'll want to decide if a memory foam mattress is right for you. We recommend to start by looking at this 9-inch king-size mattress to give you a better idea. Built of various materials, these mattresses come in your preferred choice of foam density. They provide pressure point relief, helping to ease tension in your joints, so you will wake up feeling refreshed. These memory foam mattresses boast innovative, superior motion isolation, making them great for restless sleepers, unlike traditional spring mattresses. A potential downside is that they can smell a bit like chemicals at first, so you should air them out for at least 24 hours before putting sheets on. Moreover, they aren't waterproof, so you'll need to be careful and make sure that they don't encounter too much moisture.

Innerspring Mattresses

Trying to find a good innerspring mattress? This 9-inch king-size mattress might be a good choice for you. Designed with firm edges, innerspring mattresses provide stable support and prevent roll-off. They feature various types of coils, so you can choose what's right for you depending on your preferences. They are made with various materials, so you can choose from a range of levels of comfort and foam densities. They are good at dissipating heat, allowing you to stay cool all night. These mattresses have a breathable design for proper airflow. Something to keep in mind is that they have poor motion isolation, so they aren't ideal for light sleepers, especially if you share your bed with someone else. Additionally, they sometimes make a lot of noise, so you'll hear every time your partner moves or gets out of bed.

Which Comfort Level Suits You?
Firm Mattresses

Are you searching for a firm mattress? A 9-inch king-size mattress could be a good choice for you. Improving circulation, these mattresses promote deeper sleep. They are built with a 34-36 pound indentation load deflection rating and are ideal for back sleepers. They allow for even weight distribution, which avoids pressure by balancing your body without having your back or joints sink. One downside is that these mattresses can be uncomfortable if you're not accustomed to sleeping on firm surfaces, so it might take a couple of days to get used to them. In addition, they can put strain on specific pressure points, so if you want a mattress that relieves pain in pressure points, this is not the mattress for you.

Medium Firm Mattresses

Interested in getting a medium firm mattress? A 9-inch king-size mattress could be a good choice for you. These mattresses are good for couples where one individual who prefers to sleep on their side and the other on their back or stomach. They provide proper weight distribution, so you can comfortably balance your body without having your back or joints sink. They have a 29-31 pound indentation load deflection rating and are ideal for those who switch from their back to side. Something to keep in mind is that they are more likely to become a bit lumpy or sink in over time, so it's possible that they'll be less comfortable and supportive since your body won't be aligned well.

Medium Plush Mattresses

If you're considering a medium plush mattress, a 9-inch king-size mattress could be a good choice for you. Medium plush mattresses are ideal for couples where one individual who enjoys to sleep on their stomach or side and the other on their back. They are built with a 24-26 pound indentation load deflection rating and are ideal for those who switch from their side to back. However, they may be problematic if different sleepers will be using the bed, causing the surface to sag if there is a drastic weight difference. In addition, they provide less support than other mattresses, so if you're looking for proper support while sleeping, a firmer mattress might be more suitable for your needs.