King-size mattresses are great for couples who want more room, as well as single sleepers who need space to spread out, since they have 16 inches of extra width compared to queen-size beds. King-size mattresses are more expensive and more difficult to move, so you'll want to be sure you're investing in the right model when you buy one. Here are some important considerations for choosing a king-size mattress using our lab testing and scores:
- Support and pressure relief: These are necessary for spine alignment and comfort. Look for a score of at least 7.5 for your and your partner's sleeping position and weight category.
- Motion Isolation: A king-size mattress's larger sleeping surface helps with motion isolation, since you're farther away from the source of movements, like someone getting in or out of bed. If motion is a concern, look for a motion isolation score of at least 7.5.
- Cooling: While a king-size mattress will help you feel less warm by giving you more space to spread out, hot sleepers should still look for a mattress with a cooling score of at least 8.0.
- Edge Support: A mattress with sturdy edges will let you comfortably share the entire king-size sleeping surface. Look for a score of 7.5 or more for good edge support.
- Longevity: If you invest in a king-size mattress, you'll want it to last. Avoid models that use only low-quality materials by looking for scores of at least 6.5.
We've tested over 55 mattresses, and below you'll find our recommendations for the best king-size options. We test queen-size mattresses, but the feel should be the same across sizes if the construction is the same. To recommend king-size mattresses, we prioritize motion isolation and edge support, which are especially important for couples, as well as longevity and cooling.
We've recently started testing mattresses. We purchase each unit independently from major retailers, just like you, to keep our reviews free of manufacturer influence. Each mattress undergoes the same tests to measure objective data on characteristics like firmness, cooling, and motion isolation, so you can easily compare results. Since we buy all our mattresses, we can tear them down layer by layer and isolate the mechanical properties of every component: quilted tops, foams, coils, and any special materials.
Want to learn more about how we operate? Check out our About Us page.
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Best King-Size Mattress
Side Sleeping7.4Back Sleeping7.6Stomach Sleeping7.7Longevity8.3Motion Dissipation7.8Cooling8.6See all our test resultsFirmness LevelFirm (60 Pa/mm)The Saatva Latex Hybrid is the best king mattress we've tested. We recommend this firm mattress for most couples because it suits a wide range of body types and sleeping positions, uses durable materials, and keeps you cool throughout the night, even if you sleep hot. Its balance of pressure relief and support makes it a comfortable option for average-weight and heavier side sleepers and supportive enough for most back and stomach sleepers. The springy, responsive sleeping surface prevents you from feeling stuck in place or enveloped, and sturdy edges let you use the entire king-size surface. The latex comfort layer makes it a very durable option, as that material resists sagging and indenting and helps the mattress maintain its performance for longer.
It also offers excellent cooling, especially over several hours. This makes it a good option for hot sleepers who often wake up later in the night feeling overheated, but it doesn't feel as cool when you first get into bed as some other mattresses do. Similarly, its motion isolation is good but not great. You won't feel your partner's smaller movements, but you might feel the mattress wobble for a moment with bigger movements, which is a problem if you sleep lightly. Also, while it's quite versatile overall, if you're a lighter side sleeper, you'll want a mattress with better pressure relief.
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Best King-Size Mattress For Back/Stomach Sleeping
Side Sleeping5.0Back Sleeping8.0Stomach Sleeping8.9Longevity8.6Motion Dissipation9.0Cooling8.1See all our test resultsFirmness LevelFirm (130 Pa/mm)The Sleep On Latex Hybrid is worth considering if you sleep on your back or stomach. This mattress is much firmer than our top pick, the Saatva Latex Hybrid, and it offers better support for back and stomach sleepers. For heavier individuals, it's a much better option for back and stomach sleeping, since you won't get the same level of support from the Saatva. This mattress also offers even better motion isolation. Motion dissipates much more quickly, so you're less likely to be disturbed when someone rolls over or gets into bed. The mattress's latex comfort layers give it a bouncy, responsive feel, making it easy to move around on its wide surface.
It's a very durable mattress, since the latex comfort layers will resist sagging and help the mattress maintain its support performance for longer. It's also flippable, which should help extend its lifespan. However, it's not as cooling as the previous pick. You may find it feels warm when you first get into bed, and it's not ideal if heat often prevents you from falling asleep. It performs better overnight, so you won't feel the mattress gradually getting warmer, and overall, it's cooling enough for most people.
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Best King-Size Mattress For Side Sleeping
Side Sleeping8.2Back Sleeping7.4Stomach Sleeping7.2Longevity6.8Motion Dissipation8.2Cooling8.2See all our test resultsFirmness LevelMedium (44 Pa/mm)The Helix Midnight Luxe 2025 is a great king-size mattress for side-sleeping couples. This Medium mattress offers much better pressure relief than the Sleep On Latex Hybrid, which is important for side sleepers across the weight categories. You'll sink further into its comfort layers, which gives it a more enveloping feel overall, but it's bouncy and responsive, so it still feels easy to move around on. The mattress has fantastic edge support, so you can comfortably spread out over the entire sleeping surface, and its great motion isolation performance makes it a solid option for all but the lightest sleepers.
It's cooling enough for most people, but like the previous pick, it isn't ideal if you want a mattress that feels cooling as soon as you get into bed. It's also not as durable, since its memory foam and polyfoam layers will wear out sooner than high-quality latex, but the foam is mostly dense enough to be considered good quality, which should help it resist sagging and forming permanent indentations and maintain its feel and performance for longer.
You can find more good options on our list of the best mattresses for side sleeping.
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Best King-Size Mattress For Cooling
Side Sleeping7.1Back Sleeping6.8Stomach Sleeping6.7Longevity7.4Motion Dissipation8.3Cooling9.9See all our test resultsFirmness LevelMedium (45 Pa/mm)The Purple RestorePlus Hybrid is our recommendation if you sleep hot and need a king-size mattress that will keep you cool. This Medium mattress isn't as versatile as the previous picks, but it offers good support for lighter back/stomach sleepers and enough pressure relief for average-weight and heavier side sleepers. If it suits your sleeping style, its outstanding cooling performance makes it worth trying if most mattresses make you feel overheated. Unlike the Helix Midnight Luxe 2025, it feels cool for the first hour you're in bed and for over eight hours afterward.
The grid-shaped comfort layer helps with cooling, but not everyone will like feeling the grid's shape under the mattress cover. That said, it has a springy and responsive feel that will suit hot sleepers who don't want to feel hugged or enveloped. The mattress's strong edge support lets you sleep comfortably near the edge when you need more space. It's also a reasonably durable mattress, with good-quality foam layers that will help it resist sagging.
If cooling is a big priority, you might be interested in our recommendations for the best cooling mattresses.
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Best King-Size Mattress For Back Pain
Side Sleeping7.8Back Sleeping7.5Stomach Sleeping7.3Longevity6.8Motion Dissipation8.4Cooling7.9See all our test resultsFirmness LevelMedium (44 Pa/mm)If you suffer from back pain, you might prefer the Novaform Serafina Pearl. While support and spinal alignment are important for preventing back pain, research shows that the best mattresses for back pain are Medium or Medium-Firm models that also offer good pressure relief. This Medium all-foam mattress is suitable for most back sleepers and also works for average-weight and heavier side sleepers. It has a much more enveloping feel than the Purple RestorePlus Hybrid, but it's also more supportive overall. You'll sink into it evenly, which helps keep your spine aligned without creating pressure points.
The mattress is made of dense, good-quality foam, which will help it resist sagging and maintain its support performance longer. Otherwise, it offers great motion isolation, so you won't feel your partner's every move. It's not ideal for hot sleepers, but it's cooling enough for most people. However, if you want the most sleeping space possible, you might want a mattress with sturdier edges. The edge support is okay, but you'll be less comfortable near the very edge of the bed.
For more information and recommendations, check out the best mattresses for back pain.
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Best Mid-Range King-Size Mattress
Side Sleeping7.9Back Sleeping7.7Stomach Sleeping7.6Longevity6.3Motion Dissipation9.0Cooling8.4See all our test resultsFirmness LevelMedium (46 Pa/mm)If you want more space without spending high-end prices, you might prefer the Tuft and Needle Mint. This mid-range option isn't as comfortable for lighter side sleepers as the Helix Midnight Luxe 2025, but it's comfortable for most other side sleepers and offers enough support for a range of back and stomach sleepers. Overall, its balance of pressure relief and support makes it well-suited for couples with different needs, especially because you won't feel your partner's smaller movements.
While it doesn't cost a fortune, it still offers some benefits over budget mattresses. Its great edge support means you can comfortably use the entire king-size sleeping surface. It has excellent motion dissipation, so you won't feel most of your partner's movements, and it's cool enough to keep you comfortable even if you sleep with a partner. While it's not as durable as some of the previous picks, it still uses mostly good-quality foam for its comfort layers, which will help it resist sagging for longer than some budget-friendly options.
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Best Budget King-Size Mattress
Side Sleeping8.1Back Sleeping7.3Stomach Sleeping7.1Longevity6.7Motion Dissipation9.4Cooling8.1See all our test resultsFirmness LevelMedium-Plush (39 Pa/mm)If you want to spend less on a king-size mattress, consider the Silk & Snow Mattress. This Medium-Plush all-foam mattress is a great option for couples looking for a budget-friendly king bed. Its softer feel makes it well-suited for side sleepers of any weight. It also stands out for its motion isolation, which ensures you hardly feel your partner's movements, making it worth considering if you're hoping a king-size mattress will help you sleep undisturbed.
It's cool enough for hot sleepers, and the mattress's foam is dense enough to be considered good-quality, unlike many cheap mattresses. It also offers adequate edge support, so you won't feel pushed out of bed if you end up near the side. However, if you need a solid surface for getting in and out of bed, you might find the edges compress too easily. It's also worth noting that it's not a bouncy mattress, which makes it more difficult to move around on.
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Best Cheap King-Size Mattress
Side Sleeping6.7Back Sleeping7.3Stomach Sleeping7.5Longevity6.0Motion Dissipation8.8Cooling8.3See all our test resultsFirmness LevelMedium-Firm (54 Pa/mm)The best cheap king-size mattress we've tested is the Allswell Hybrid. This inexpensive mattress includes lower-quality foams and isn't as durable as the Silk & Snow Mattress, but if you want more sleeping space at an affordable price, it's a versatile option with a solid all-around performance. It's best suited for back and stomach sleepers, since it provides decent support for most people and enough pressure relief for average-weight and heavier side sleepers.
The mattress's excellent motion isolation makes it a good option for couples, since you won't feel movement throughout the mattress, and it dissipates quickly, so you're less likely to wake up when someone rolls over or gets out of bed. It has sturdy edges, so you won't feel pushed out of bed if you sleep near the side. It'll also keep most people comfortably cool overnight, although you might find it a bit stuffy when you first get into bed.
Notable Mentions
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Casper Snow:
The Casper Snow is a high-end Medium mattress that you might prefer to the Saatva Latex Hybrid if you like a mattress with a more enveloping, hugging feel. It's very versatile and better suited to lighter side sleepers in particular, but it's not as durable and might make you feel stuck in place.
See our review -
Purple Mattress:
The Purple Mattress is a less expensive, all-foam mattress that's nearly as cooling as the Purple RestorePlus Hybrid. It's a good option if cooling is a priority and you're not looking for a high-end mattress, but its edges aren't as sturdy, which can make your king-size bed feel slightly smaller.
See our review
All Reviews
These recommendations above are what we think currently represent the best king-size mattresses for most people. Alongside test results, we factor in visitor feedback, availability, and, of course, price.
That said, the best mattress for you depends on your and your partner's sleeping positions, body types, and specific preferences, like cooling or motion dissipation. If you want to choose yourself, here's a list of all of our mattress reviews.