Best King Size Memory Foam Mattress (2024)

1. Amerisleep AS3

The Amerisleep AS3 mattress is one of the best memory foam mattresses on the market. You’ll love the feel of contouring memory foam as it molds to your body, relieving pressure points. Unlike traditional memory foam mattresses, the AS3 doesn’t trap heat because it contains porous plant-based foams, so can sleep better without waking up feeling hot—this is especially beneficial for hot sleepers!

The AS3 is medium in firmness and recommended for side, combination, and back sleepers. It balances comfort and support and is also good for couples who need a mattress to accommodate more than one sleep style or body type.

The first layer of the medium AS3 is Amerisleep’s Bio-Pur®. This eco-friendly layer contains plant-based oils, transforming traditional memory foam into a breathable, more responsive foam. Plus, because Bio-Pur® is so responsive, you won’t feel like you’re struggling to switch sleeping positions when resting on top of the AS3.

Below the adaptable comfort layer is the AS3’s transition layer of Affinity and HIVE® technology. This layer contains hundreds of hexagonal-shaped segments arranged in five zones—you’ll feel softness under your shoulders and hips, and firmness under your head, back, and legs. The HIVE® technology within this transition layer cushions pressure points and encourages spinal alignment to facilitate healthy sleeping positions and ease aches and pains.

The final layer of the AS3 is sturdyBio-Core®. Bio-Core® is a durable base foam designed to evenly distribute body weight and resist sagging. With Bio-Core®, you can enjoy consistent support, and you won’t have to worry about back pain from soft spots.

Every Amerisleep mattress comes with a 100-night sleep trial and a lengthy 20-year warranty. If you don’t absolutely love the AS3 after breaking the bed in, Amerisleep gives you the option to return it for a full refund.

2. Zoma Mattress

The Zoma Mattress is not only an excellent cooling mattress, but it’s also the perfect choice for those who lead an active lifestyle because it promotes deeper sleep and faster recovery. The cool and breathable foam layers of this mattress draw heat away from the body and improve circulation, so muscles receive adequate cushioning and you wake up feeling refreshed.

Like the AS3 mattress we discussed above, the Zoma is also a medium mattress. However, many reviews of the bed mention it feeling soft and cushioning, so it’s safe to say this bed falls on the softer side of medium. With that, the Zoma is a comfortable option for side, back, and combination sleepers.

The comfort layer of the Zoma is 2 inches of gel memory foam to absorb and disperse body heat, allowing you to enjoy a cooler sleep without night sweats. Within this layer lies Triangulex™ technology. Triangulex™ delivers zoned support through triangle-shaped segments. These segments fall below your shoulders and hips to allow for deeper compression. Under the torso, however, Triangulex™ is flat and firm for sturdier support.

Below the comfort layer is a 2-inch layer of latex-like Reactiv™, a responsive and durable foam in place to prevent you from sinking too deeply. Reactiv’s™ buoyancy also makes it easier to change sleeping positions on the Zoma. The addition of this transition layer also enhances pressure relief, reducing buildup in the shoulders and hips.

At the base of the bed, you’ll find a notably firm support layer called Support+. This long-lasting poly-foam reinforces the top layers to prevent premature sagging. Plus, Zoma backs their mattress with a 10-year warranty covering sags as little as .75 inches—so should your bed ever develop visible indentations, Zoma will replace it for you free of charge.

Zoma Sleep offers a risk-free 100-night sleep trial with every mattress purchase. If you find the mattress isn’t a good fit after breaking it in, simply give Zoma’s customer support team a call and they can initiate a refund.

3. Vaya Mattress

The Vaya Mattress is an excellent all-foam mattress for those on a budget since it costs less than $800 for a king size. (Similar models can run higher than $1,000!) When shopping online with Vaya Sleep, you can enjoy the comfort of foam and save yourself a few extra bucks.

The Vaya Mattress is designed to offer an even mix of comfort and support and is recommended for all sleep styles because it is both contouring and responsive. That said, some stomach sleepers may find the Vaya too soft.

Altogether, the Vaya measures 12 inches thick and contains a 3-inch comfort layer and a 9-inch core.

The comfort layer is made with Vaya Comfort Foam, a plush material that forms to your body’s curves without trapping heat. Despite this layer’s softness, it offers plenty of support to keep you in a neutral position. And, if you tend to sleep hot, you’ll love how breathable Vaya’s Comfort Foam feels—you won’t have to worry about waking up with night sweats anymore!

Below the cushioning comfort layer is thick, sturdy Vaya Support Foam. This layer distributes body weight to further prevent pressure points while offering firm support for you and your sleeping partner. Vaya Support Foam is durable enough to withstand regular wear and tear without the risk of developing soft spots.

Like most online mattresses, the Vaya comes with a 100-night sleep trial, free shipping, and free returns. After a couple of months, you may return the mattress for a full refund. However, if you decide to keep the bed, Vaya offers a 10-year warranty with every mattress to back your investment.

What is a King Size Mattress?

King size mattresses were first introduced in the 1950s to offer more personal sleeping space for couples. Full size beds used to be the go-to size for couples, until queen and king sizes rose in popularity.

Today, kings are a favorite size among couples. Measuring 76 inches by 80 inches, the king size mattress is the equivalent to two twin XL mattresses. Each person can enjoy 38 inches of personal space. With a king bed, you’re less likely to bump into your partner while sleeping. You also have more room to stretch your legs, so neither of you feels cramped.

Considering their large size, king size beds fit comfortably inside master bedrooms measuring at least 13 feet by 13 feet. That way, you have room for other furniture and additional walking space. For smaller spaces, a queen, full, or twin size mattress might be better.

All mattress types are available in the standard king size—memory foam, latex, innerspring, and hybrid mattresses. However, the one mattress type that stands out is memory foam.

Why Choose Memory Foam?

Memory foam didn’t appear inside mattresses until the 1990s, but since then, it’s become one of the most popular mattress types the industry has to offer. Memory foam is polyurethane foam treated with chemicals to give the material more viscosity. When you lie on memory foam, body heat and pressure soften the material, causing it to form to your body’s curves.

Memory foam’s body contouring properties effectively relieve pressure points better than other mattress materials, like innerspring coils. Coil beds can’t conform as well as memory foam mattresses and may worsen pressure build-up in heavier sections of your body, like the shoulders and hips.

How to Find the Best King Size Memory Foam Mattress

Before deciding on a king size memory foam model, consider doing some extra research to make sure you get the best mattress. Factors like cooling materials, foam quality, price, and possible sleep trials and warranties can narrow down your options and help you find the best king size mattress.

Cooling Materials

Traditional memory foam can retain heat because of its dense structure. The compact material doesn’t allow for much airflow, so when you lie on traditional memory foam, body heat is trapped because it doesn’t have any way to escape. However, choosing a memory foam mattress with cooling materials can improve airflow and regulate body temperature.

Gel memory foam mattresses, one of the more popular cooling mattress types, absorb and dissipate body heat to regulate temperature.

Another common cooling material is plant-based oils. During the manufacturing process, a portion of the petroleum is replaced with plant-based oil, creating a breathable foam that’s more responsive. You’re less likely to feel stuck inside the bed and may find it easier to change sleeping positions.

Copper and graphite are two common materials mattress manufacturers use to cool down mattresses. Copper and graphite naturally pull heat away from the body. Copper has added antimicrobial properties, making the mattress resistant to dust mites and bacteria.

Quality

To find a high-quality memory foam mattress, take a look at each layer’s ILD rating and density. These measurements give you an idea of how well the mattress can stand up to constant use. If the mattress manufacturer doesn’t list either the ILD rating or density, the bed may contain cheap layers instead of high-quality materials and should be avoided.

ILD Rating

ILD or Indentation Load Deflection measures how much pressure it takes to make a 4-inch indentation on the mattress’s surface. ILD ratings run between 8 to 20 in the comfort layer. For the best comfort, the top foam layer should have an ILD rating of 10. The foam won’t feel too soft and can withstand wear and tear.

Density

Foam density determines how well a mattress supports the body. Density is measured in pounds per cubic square foot.

Memory Foam:

• Low: 2.5 to 3.9
• Medium: 4.0 to 5.4
• High: 5.5 and higher

Poly-foam:

• Low: 1.8 and lower
• Medium: 1.8 to 2.5
• High: 2.5 and higher

Lower density foams tend to break down faster because they don’t contain as much foam as a higher density foam. In the same sense, a king size memory foam mattress may cost more if the layers contain high-density foam because the foam layer contains more material.

Price

King size memory foam mattresses are more expensive because of their size. The current price tag for a king size memory foam mattress is between $600 to $5,000. Cooling materials and high-density foam layers can drive up the price, but you may feel the cost is worth getting better sleep.

Another factor you want to consider when setting a budget is shipping and handling fees. Many mattress manufacturers offer free shipping, but if you don’t like the bed and want to exchange it, you may have to pay shipping and handling fees.

If a king size mattress is currently out of your reach, you can still enjoy the conforming feel of memory foam with a king size mattress topper.

Sleep Trials and Warranties

Sleep trials allow the customer to try out a new mattress in the comfort of their own home. Most last between 90 to 120 nights, but some companies may require you to keep the bed at least 30 days.

It can take your body a few weeks to adjust to a new sleep surface, and the mandatory 30-day period ensures you’ve broken it in. If you don’t like the bed, most mattress companies will issue a refund. You may also exchange the bed for a different model.

The warranty covers manufacturing defects and sagging up to 1 inch. This measurement depends on the brand. Most new mattresses come with a standard 10-year warranty and can’t be transferred to another person. Warranties don’t cover liquid damage, so it might be a good idea to invest in a mattress protector.

Be sure to read the fine print before making a decision. That way you’re not stuck with a cheap, uncomfortable bed.

Consider an Adjustable Base

If you’re looking to optimize your comfort level, consider an adjustable base. An adjustable base allows you to elevate your upper and lower body electronically with the push of a button. Raising your head and legs can further reduce pressure points, especially in heavier sections of your body.

Elevating your head and feet may also improve circulation and reduce snoring. Some adjustable beds include special features such as under-bed lighting and full-body massage to make your night’s sleep even more comfortable.

FAQs

Do you flip memory foam mattresses?

You don’t need to flip a memory foam mattress. Modern mattresses have a one-sided structure, so the bed doesn’t need to be flipped. It’s still recommended that you rotate your mattress 180 degrees every three months instead even to wear and tear.

How long does a memory foam mattress last?

High-quality memory foam mattresses typically last 7 to 9 years. A mattress’s lifespan depends on how well it’s cared for and how often it’s used. If the memory foam mattress is meant as a guest bed, you could get more use out of the bed, because the mattress isn’t used as often.

Can I place a memory foam mattress on a box spring?

Memory foam shouldn’t be placed on a box spring. Box springs can’t support the heavy, dense structure, and could end up damaging the mattress. Instead, place the memory foam mattress on a solid surface, like a platform bed. Box springs are better for innerspring mattresses because the coils act as shock-absorbers.

Is an innerspring mattress better than memory foam?

Memory foam relieves pressure points, is silent, and isolates motion—three things innersprings are not known for. Innersprings are naturally cool and provide a bouncy surface, but because they have a thin comfort layer, you’re more likely to wake up feeling sore on an innerspring. Overall, we recommend memory foam over innersprings.

Is memory foam better for side sleepers?

Memory foam is the perfect mattress material for side sleepers. It contours to the body and relieves pressure points throughout the body, especially in the shoulders and hips. Side sleeping is one of the healthiest sleep positions, but it places more pressure on the shoulders and hips. Memory foam reduces this pressure for a better night’s sleep. You’re less likely to wake up feeling sore.

Conclusion

King size memory foam mattresses are an excellent choice for those seeking the ultimate comfort experience. The spacious sleeping area gives plenty of room for two people to stretch out on a comfortable mattress without feeling crowded.

Plus, memory foam reduces pressure build-up, so you can get a good night’s sleep and wake up with fewer aches and pains. It may seem overwhelming with so many available options, but if you do your research, you’ll find the best king size memory foam mattress in no time.