The Best King Size Mattresses

Top 7 Best King Size Mattresses for 2020

Here are the best king size mattresses, listed according to the overall quality and comfort of the mattress.

1. Amerisleep AS5 King Mattress

The Amerisleep AS5 king size mattress is #1 on our list because of its combination of quality, suitability for a wide range of sleepers, and value for money.

Amerisleep AS5 mattresses are available as an all-foam king size mattress or a hybrid mattress with a memory foam upper section and classic innerspring coils.

I prefer the hybrid version of the Amerisleep AS5 because I like the more traditional feel that innerspring coils provide. In addition to providing more resistance and bounce under the contouring foam, innerspring coils provide greater airflow and breathability.

Amerisleep has incorporated a zoned support system into the king size AS5 mattress. This system provides more support for your back and is softer below the hips. By using different density memory foam for these areas, Amerisleep helps the sleeper maintain a more natural sleeping position.

Feeling increased motion transfer is usually a downside of incorporating innerspring coils in a mattress, though I could detect little difference in this case.

It should be noted that my preference for the hybrid AS5 mattress is exactly that, a preference. Mattresses are very personal and once you reach this level of quality, preferences for one material over another come down to the sleeper and not the mattress. My son preferred the all-foam version of the AS5.

Amerisleep’s AS5 all-foam king size mattress is the best choice for sleepers that prefer greater contouring and a feel of being cradled.

The foam that Amerisleep uses for the AS5 mattress is an open-cell memory foam, designed to provide better cooling.

The all-foam version of the AS5 mattress is divided into 5 comfort zones. This design is a more intelligent approach to support as heavier parts of the body are given the most support. A uniform density memory foam would result in not enough support being given to the hips and upper body while your legs would be held too firmly and this would result in pain, usually in the hip joint area.

The 5 zone system that Amerisleep uses for the AS5 mattress helps the sleeper have proportionally uniform support for all of the parts of their body. It’s a good design and well thought out here.

As far as motion isolation goes, any memory foam mattress is good at motion isolation but the zoned system reduces motion transfer to as close to zero as possible.

Both versions of the Amerisleep’s AS5 king size mattress come with a 100-night trial period, a 20-year warranty, and free shipping. Amerisleep makes the AS5 in standard king, California King, and Split King sizes.

Amerisleep’s AS5 is made in the USA.

2. Casper Original Mattress

The Casper Original is a twelve-inch thick, multilayer foam mattress. It feels comfortable while still giving you a slight bounce.

The mattress has a soft 100% polyester cover, followed by a top layer of breathable open-cell foam to maximize airflow and help you stay cooler.

The layers of this king mattress are made of high-density, zoned transition, and durable foams. Casper is said to help alleviate hip pain without compromising comfort. People with conditions like scoliosis and arthritis might find this incredibly helpful for pain relief.

If extra firmness is required, you can opt to add pocketed innerspring coils that are available in the hybrid option. The innerspring pocket coil system at the bottom will give it a more firm feel, so it will be easier to move on the bed. Also, the pocket coil springs can help you get up easier and would be especially helpful for an older person, or someone of a larger body size, who has trouble getting out of bed.

The Casper provides both contouring support and plushness. It is soft enough for a pleasant sleep, with decent motion isolation, which makes it great for couples. This feature is especially crucial if your partner is a light sleeper or easily awakened by movements.

However, some of their mattresses do have a disadvantage of poor side strength. Edge support is basically how much a mattress holds you up or pushes against you when in use and mattresses with firmer edges reduce the sagging and falling feeling you get at the sides. It also gives you a better brace sitting at the side of the bed and is quite important for someone who is pregnant, experiences joint pain, or other health conditions that make it hard to get out of bed.

Unfortunately, these new mattresses have a sagging feeling with almost no push back when you attempt to get up. You should take this disadvantage into consideration when making your decision, especially if being easy to get up from is something you really require.

The Casper company established itself in the mattress industry by committing themselves to studying the science of sleep. They are driven to help you get the rest you need by catering to the needs of the customer, promising “innovative sleep products”. Their array of products contains some of the top mattresses on the market.

Casper is CertiPUR-US certified, so it is made without ozone-depleting chemicals (refer to the FAQ for details on CertiPUR-US certification) so the materials used in manufacturing the mattress are safe, with no harmful emissions.

Casper provides a ten-year warranty, free delivery. However, it is at a slight disadvantage as some users have complained of a particular smell that takes a few days to completely disappear.

At a price point of $1,195 for the original version and $1,395 for the hybrid version, it’s not the cheapest mattress on the market but it has innovative features and you can test it out during the trial period to see if it’s an ideal fit for you.

3. BedInABox Original Mattress

The BedInABox Original is a mattress that is designed with BedInABox’s patented advanced gel-infused memory foam that regulates heat and contours to your body.

This mattress provides pressure relief as well as more even weight distribution on the bed. Since everyone has different pressure points in their body, this feature is important for all types of sleepers.

The BedInABox Original’s first comfort layer also uses an open-cell technology, encouraging better airflow and preventing the beds from becoming too hot. The mattress takes its shape quickly when you lay down, making it more comfortable for you to change positions during the night. Those who move around frequently will find this most comforting.

The second layer of the mattress consists of eight inches of high-quality heavy memory foam called Sure Align, which is much stronger than we found in other mattresses. It helps to realign your spine to alleviate back pain and body aches. For those with back pain or spine aligning issues, this is a popular choice.

The BedInABox Original is encased in a soft knit polyester cover which is very durable, resists abrasion, is quick-drying, and soft to touch. It also helps make the mattress easy to clean.

BedInABox Original mattresses are rated 5 on the firmness scale so it is a medium feel mattress with adequate support.

BedInABox offers a warranty of twenty years, indicating that the manufacturer is confident that its product can stand the test of time. If you buy online, BedInABox also offers the option of paying in monthly installments that matches your budget.

The BedInABox company also provides free shipping and returns with a 120-night trial for customers who are not yet sure if they want to commit to their mattresses. All in all, BedInABox’s Original mattress comes with a price tag of $979 for their king size mattresses and it seems like a good deal for one of the top king size beds.

4. Tuft and Needle King Mattress

Tuft & Needle manufactures poly-foam mattresses and their Original 10-inch mattress comes with Adaptive Foam for optimum comfort.

As a medium-firm mattress, the Tuft & Needle is rated 6.5 on the firmness scale, and is one of the top king size mattresses for those who prefer more than one sleeping position or if firmer bedding is preferred. Tuft & Needle provides substantial pressure relief for stomach, back, and side sleepers. This mattress props up and aligns the spine and hips with ease, which can help to ease back pain. Tuft & Needle mattresses are suitable for stomach sleepers as they are firmer to reduce pressure around the chest area.

The mattress provides excellent motion isolation and is perfect for couples. We also found that the mattress has heavier construction around the edges to avoid the feeling of rolling off when you’re on the sides.

The bedding is CertiPUR-US and Greenguard Gold (low chemical emissions) certified. Being environmentally friendly, the mattress produces no harmful emissions that will affect the user’s health. Additionally, this model holds the Standard 100 certification by Oeko-Tex. This means the fabrics close to the skin are tested for harmful chemicals, so you know that it is safe to use and will not harm your skin, that’s important if you’re sensitive to allergens and manufacturing chemicals.

The company offers a set which includes their king size memory foam mattress as well as a pillow made from their adaptive breathable memory foam and cooling gel for a total of $950. Overall, it’s a decent price for one of the best mattresses available and it provides the flexibility of accommodating various sleeping positions and preferences.

5. Sleep Innovations Shiloh

The Sleep Innovations Shiloh mattress is a 12-inch memory foam mattress and is one of their most popular mattresses online.

The first of two layers is their SureTemp memory foam, an open-cell formulation that supports you well while allowing air to flow through easily, preventing you from getting too hot. Keeping your temperature regulated while asleep is crucial for being well-rested so this patented technology seems to be a favorite among users as many say it helps them stay cooler.

Additionally, there are 9.5 inches of Support Plus foam to give the Shiloh a solid base that reduces motion on these beds. We found the motion isolation to be excellent, so you can expect almost no motion transfer on the Shiloh. This base will help with back pain and spine alignment while keeping you comfortable.

The Shiloh is suggested for users with any sort of sleeping position as it has a rating of 5.5, giving it a moderate softness feel. It is firm enough for active sleepers and conforms easily to the body.

A slight disadvantage of the Shiloh is its poor edge support, as we found that it had a slight sinking feeling towards the sides. For those who require more support from your mattress or are slightly heavier than the average user, this might change your decision on purchasing the Shiloh.

The company offers a 20-year guarantee that speaks to their confidence in their mattresses and the durability they provide. For a mattress that cools even more than the Shiloh, it’s worth checking out the other mattresses Sleep Innovations offers.

As a bonus, the manufacturer includes a deluxe quilted cover together with the mattress for a more luxurious look. If you’re quite particular about how your mattress looks under the sheets, you’ll be pleased with this addition.

The Sleep Innovations Shiloh is one of the least expensive mattresses we have on our list, at $549.99. In addition, it is CertiPUR-US certified and comes with a 100-night free trial.

6. LUCID 10-Inch Hybrid Bamboo Charcoal and Aloe Vera

Lucid’s “10-Inch Bamboo Charcoal and Aloe Vera” hybrid mattress is a mixed foam mattress that consists of memory foam, a poly-foam, and special pocketed innerspring coils.

The mattress comes with a Tencel cover, which is environmentally sustainable and non-toxic. If you’re sensitive to chemicals used in manufacturing fabric, this cover will not be harmful or irritating to your skin. Tencel is made from cellulose fibers and is naturally biodegradable.

Aside from it being non-toxic, Tencel is also strong and soft to the touch, making it a superb cover for the Lucid 10-Inch Bamboo Charcoal and Aloe Vera hybrid mattress. Not many manufactures choose Tencel for their mattress cover so we were pleasantly surprised to find that Lucid used it in this mattress.

Lucid named this model the “10-Inch Bamboo Charcoal and Aloe Vera mattress” because it incorporates those materials into the mattress. Its top layer is 1.5 inches of bamboo charcoal memory foam. Let’s talk about the benefits of having charcoal infused into mattresses. Charcoal has been utilized for a long time to absorb and eliminate unpleasant odors, a nice addition to have in mattresses because a mattress is used every day and can build up oils over time.

Charcoal helps keep unpleasant odors away and maintain a clean atmosphere around your sleeping area. Charcoal also works to absorb VOC’s (Volatile Organic Compounds), which are damaging chemical vapors that result in lower indoor air quality.

In terms of comfort, the memory foam provides soft plushness and gives a gentle “sink in” experience. Below this top layer, there is one inch of aloe vera infused memory foam. Both of these two layers give the bedding a fresh feel and we found that it did well with not becoming too hot.

The main support layer of the mattress consists of 5.5 inches of pocketed innerspring coils that add to the “bounce”. The innerspring coils are individually wrapped so they are optimal for improving airflow in this mattress. We found moving around to be easy with solid push back, and it was easy to get up.

The Lucid 10-Inch Bamboo Charcoal and Aloe Vera mattress has a medium-firm rating of 6.5, making this mattress a good choice for side sleepers as the support is better for the body. However, the mattress seems a little soft and lacking in firm support that is required for stomach sleepers. For those looking for the best innerspring mattress for side and back sleeping positions, this is one of the top king size mattresses to consider.

The Lucid 10-Inch Bamboo Charcoal and Aloe Vera mattress distributes movement well over the mattress surface. Also, the pocketed spring coils work well to isolate any movement.

Lucid also includes a classy circular knit cover with the mattress so it looks and feels luxurious, helping you feel pampered every night. Priced under $450 and an Amazon customer favorite, it is great for those sensitive to odors or shopping for a mattress that does more than just give you a good night’s rest. Lucid provides free delivery and a 10-year warranty for this mattress.

7. Zinus Green Tea Memory Foam Mattress

This Zinus “Green Tea Memory Foam” mattress uses green tea extract and bio-plant oil while still being very affordable.

If you’re looking for a unique king size mattress but you are on a limited budget, Zinus offers a solid product.

Zinus incorporated green tea, a natural anti-oxidant, into the foam of this mattress along with ActivCharcoal (purified charcoal) to reduce and absorb unpleasant odors. For those worried about odors, this air-purifying material is also CertiPUR-US certified so you do not have to worry about harmful chemicals being used during the manufacturing process.

This Zinus mattress has five layers and it starts with a microfiber layer that is quilted to the knitted jacquard cover.

Viscolatex consists mostly of latex with foam padding so both materials work hand in hand to provide pressure relief. A disadvantage of using a mattress made of latex is that it tends to get hot quite easily. For those interested in a mattress that cools itself thoroughly, this Zinus mattress will not be the top choice for you.

Another slight disadvantage of the Zinus is poor edge support as we felt a sinking feeling when you are on the edge of the bed. This is probably because it is solely made of latex and memory foam and lacks the bounce effect innerspring coils offer.

This king size mattress has a firmness rating of 5 and is marketed as the best mattress for back sleepers as the support of pressure points is excellent.

Being shipped as a bed in a box, it needs 72 hours to fully expand and decompress after it is out of the shipping box. Zinus also advises that the climate can affect mattress expansion, especially in cold weather where you will have to wait a while longer. Some users have reported experiencing smells after it’s unboxed, so a waiting period of 72 hours is also needed for any smell to dissipate.

A king size, 12-inch thick version of this mattress has a price of $410 with free delivery.

King Size Mattress Buyer’s Guide

This buyer’s guide to king size mattresses will cover a few factors worth considering before making your buying decision.

Buying a king size mattress of any quality is expensive, so it is important to understand your options, where you might adjust your requirements, and what features should not be compromised.

Types of King Size Mattresses

Although you’ll hear the term king size mattress used as though there is only one universal size, there are several types of king size mattresses available. These less common sizes, though a little harder to find, all have their advantages and may be worth considering.

Our personal favorite is the massive Alaska king, but it is only for those with a budget and a room big enough to accommodate it.

King (Standard)

A standard king size bed is 76 inches by 80 inches, which is 16 inches wider than a queen and nearly a square.

California King

The California king mattress is 72 inches wide and 84 inches long, which makes it three inches more narrow and 4 inches longer than a classic king size mattress.

If you’re 6 feet tall or can fit comfortably in any car you have ever driven, you will not need more length than a classic king mattress can provide. The only reason to buy a California king mattress is the extra length that taller people may need to be comfortable.

If having enough headroom is always a problem for you, it may be worth considering buying a California king mattress and giving up a little width in exchange for extra legroom.

Do bear in mind that standard king size sheets will not fit these beds.

Wyoming King

A Wyoming king mattress is perfectly square, with dimensions of exactly 84 inches by 84 inches. While true that you would be gaining a whole foot over a classic king size mattress, the extra cost and lack of choices for Wyoming king mattresses make it difficult to recommend.

Texas King

Texas king mattresses, also known as Super King, are 80 inches wide by 98 inches long. They say everything is bigger in Texas, and these are definitely big enough to go to bed with your hat on. But, unless mattress length is consistently a problem, most people will not find the extra length very useful.

Alaskan King

The Alaskan king is the biggest mattress size made, measuring a whopping 9 feet by 9 feet. If you’re buying the biggest and the best, the Alaskan king is the only type you’ll want to consider.

You will need to keep in mind that Alaskan kings will need to find special sheets, pillows, and bedding, and you’ll absolutely want to measure your bedroom carefully to be sure you have enough room for this giant.

Split King

A split king is made of two separate mattresses that are pushed together to create a king size bed. The advantage of this is that each mattress can be a different firmness, which is great for couples that have different sleeping preferences. The disadvantage of this type of mattress setup is that you must contend with the seam in the middle, making it a less than ideal choice for two people that sleep closely.

Comfort

The overall comfort of a mattress depends on factors like material, softness, firmness, support, and airflow. Certain memory foam mattresses are known to heat up as they are exposed to body heat and this makes sleeping uncomfortable, but mattress manufactures have made technological advances to combat this particular heating issue so customers now have many choices of mattresses made with various types of cooling materials.

From our testing, we found that a king size mattress was more comfortable than a queen, full, or twin XL mattress.

Support

You should also take into consideration what sort of firmness you prefer with your mattress. Since there are many types and degrees of firmness to pick from, you can choose between firm, medium, or plush for your sleeping needs. Identifying how you like your mattress to feel is also important to consider. For example, do you like to sink down into the mattress or float? Knowing this will give you an idea if you should be shopping for a memory foam, latex, or hybrid mattress.

Sleeping Positions

Your favorite sleeping position will determine what mattress will be the most comfortable for you.

A mattress that is perfect for someone that prefers a stomach sleeping position will likely be uncomfortable if you prefer sleeping on your side.

Studies show that side sleepers prefer a plush mattress since they require more cushioning. Back sleepers require support for the spine with cushioning so a firm to moderately plush mattress is ideal. People who like to sleep on their stomach require the most support and any firm to medium mattress is better for them.

For Couples

Couples usually prefer a mattress with good motion isolation.

This is useful both from the standpoint of not waking up your partner and because you may find that more vigorous activities feel better with less bounce.

Space

While having a large mattress is great, you will need to be sure that you have enough space in your bedroom before deciding on your purchase. Having enough space to accommodate a king size mattress is important as you and your partner would be uncomfortable in a cramped room.

If the room is small, a queen mattress is generally preferable since it is better to have less space than to have a crowded bedroom. If you are sleeping alone, you probably won’t notice much difference between a queen and king size mattress.

Durability

Another element worth considering is mattress durability. Most high-quality luxury mattresses come with a minimum warranty of five to ten years. Realistically, a mattress should be replaced after five to seven years of use, depending on its quality. A really high quality mattress can last up to ten years if it is well taken care of.

Special Features

Luxury bedding may have special features like patented fabric covers that regulate airflow, hypoallergenic materials, odor absorption, and hybrid construction. Our advice is to consider how important each of these is to you so you know what to look for before making your mattress purchase.

Sleep Trials and Warranties

Most reputable mattress brands will offer a trial period of around 100 nights with some trials extending up to 18 months. If for any reason you are not satisfied with the mattress, you could arrange for a return within the trial period and you would get 100% of your money back. Do check the delivery and return policy of your top choices as you sometimes need to pay for delivery fees even with a free trial.

King size mattresses are often expensive and the best way to know if a mattress is suitable for you is to try it.

Warranties are important for a mattress that will receive daily wear for many years.

For a long time, 10-year warranties were standard. Today, some premium mattress brands offer a lifetime guarantee. These mattresses aren’t cheap, so a lifetime warranty can be a pretty good bonus.

What Types of Materials are Best for a King?

The materials the mattress is made of determine the comfort and product lifespan.

It’s easy to focus solely on how a mattress feels when you first lay down. However, initial comfort does not guarantee you won’t be hurting or sweating after 3 hours in the bed.

There are cost, comfort, and heat dissipation advantages to different construction methods.

Coils

If you grew up in the ’80s or before, you slept on mattresses with coil springs. Coils have their advantages and offer a durability that can’t be beaten, but they can also introduce noise (the classic bed squeak) and motion transfer.

Most good mattresses these days use innerspring coils, which help to isolate motion and are a huge advancement over what we grew up with.

Memory Foam

The term memory foam has become a bit of a catch-all for any foam that is slow to compress or decompress. It is essentially slow to react to changes. Whether this is positive or negative is really a matter of personal preference, though there are many claims of it helping with spine alignment and back pain.

Latex Foam

Latex rubber foam, whether Talalay or Dunlop latex, offers a quicker response than other foam material. Both types are made from the sap of rubber trees and give a springy feel you would expect.

Tatalay latex is most often used as a softer layer in luxury bedding, as it has a light and spongy consistency.

Dunlop latex is a little more crude, having particles of sediment from the production process. This makes it less suitable as a top layer, but excellent in base layers.

Hybrid Mattresses

Hybrid mattresses mix and match the materials used in the construction of the mattress. For instance, a hybrid mattress may have innerspring coils as the base, with a high density polyfoam in the middle layer, and Tatalay latex for the top comfort layer.

Personally, I prefer to sleep on a really good hybrid mattress as their engineering is more refined and this mattress type is generally of better quality for foam alone.

King Size Mattress FAQ

How big is a king-sized mattress compared to a California king mattress?

A classic king size mattress is 76 inches wide and 80 inches in length and a California king mattress measures slightly longer at 72 inches wide and 84 inches long. This makes the California king mattress a more suitable option for taller sleepers.

How is firmness measured?

Oddly enough, there is no industry standard for measuring and rating the firmness of a mattress. For our reviews, we prefer to use a bowling ball and measure the depth of the depression, then adjust that number based on how it feels during actual use.

Getting the firmness you need from a mattress is crucial as it determines the support you get for your pressure points. If a bed is not very supportive, you will not get a good night’s sleep and will wake up with aches and pains, resulting in a lot of sleepless nights.

Is a bed frame important?

Using a bed frame is important for supporting your mattress properly and allowing air to circulate around your mattress and box springs.

Limited air circulation can encourage mold growth in and around your mattress. For this reason, we strongly recommend using a bed frame with any mattress.

Bed frames come in many different forms and there are various types and styles that are differentiated by the type of support, fashion, and design preferences. So making sure you have a supportive bed frame as the external base is crucial for getting the most out of the mattress.

How much does a king cost?

Prices of king mattresses vary widely and can range from $1,000 to well over $10,000. A quality mattress will generally be in the $3,000 to $5,000 range.

Are all king size mattresses the same size?

Not all king mattresses are the same size. A standard king is 76 inches wide by 80 inches long, but less common dimensions like the huge Alaska king (9 ft by 9ft) are available at a premium.

What is CertiPUR-US certification?

Products that are CertiPUR-US certified confirms that the products are:

• Made without ozone depletes
• Made without PBDE flame retardants
• Made without mercury, lead, and other heavy materials
• Made without phthalates regulated by Consumer Product Safety Commission
• Low VOC (Volatile Organic Compound) emissions for indoor air quality

How much do I need to spend?

A budget of $200 – $500 is enough if you want to upgrade to a king size mattress.

Conclusion

With so many choices available, there is a king size mattress for everyone’s needs, sleep habits, and budget. I recommend deciding on the type of mattress you prefer (foam, innerspring coil, or hybrid), as well as the firmness level that you prefer, and then purchasing the best mattress at the upper end of your price range.

Buying a king size mattress is a major decision, both because of the cost and because having restful sleep is important to your health and wellbeing. For something that you will use every day and that will affect your life this much, it is wise not to skimp on quality or compromise on comfort.