I Spent Months Searching for the Best King-Size Mattresses—Here’s My Short List

Upgrading from a queen-size bed to a king has been a long-running dream of mine. For years it wasn’t feasible thanks to a pint-size NYC apartment, and then it just felt like too much work (and money!). It’s not just the mattress research that was overwhelming. There’s a new frame to consider, bedding, pillows, and…possibly a larger rug? 

Then two years after my daughter was born, right when I truly understood the meaning of sleep deprivation—being a first-time parent and working mom is no joke—I decided I could wait no longer. After all, a king-size bed is really only the equivalent width of two twin-size mattresses pushed together. And when you think about it that way, it’s not so wild, right? I spent weeks researching the best king-size mattresses—interrogating friends, family, and Instagram acquaintances; taking online Find Your Match quizzes; poring over the minutiae on each brand’s site; reading articles on the best affordable mattresses; and popping into showrooms so I could try them firsthand. 

There were two big takeaways from the search. One was that finding the right mattress is hyper-personal, so you can’t, and shouldn’t, rely solely on a friend’s recommendation (my breakdown of what to consider can be found here). And regardless of the higher price tag, purchasing one made with natural fibers was important to me. The latter became an extremely helpful guidepost as I parsed through the supersaturated world of mattresses, which often felt purposefully confusing. And ultimately, it’s what helped me whittle my short list down to hybrid choices, which use a combination of two or more support structures—coils and latex, for example. Consider this a helpful jumping-off point, and take advantage of trial periods, which range from 90 days to one year. The bottom line is: There’s really no shortcut to finding your ideal mattress—you just have to try them.

My Short List

• Best overall: Avocado Green Mattress
• Best value: Eco Terra Hybrid Latex Mattress
• Best customizable: Naturepedic EOS Classic Organic Mattress
• Best luxury: Birch Luxe Natural Mattress

Best Overall: Avocado Green Mattress

Trial period: One year | Warranty: 25 years | Firmness: Medium-firm 

Why it stands out: When you consider price, materials, certifications, latex-topper thickness, trial period, and warranty, this mattress comes out on top.

After debating and weighing a huge range of factors, from price and construction to materials and certifications, Avocado’s Green mattress surfaced as the clear winner. If there’s a certification to be had, this mattress has it. The brand uses 3 inches of certified organic latex on top of innerspring coils, as well as a layer of certified, 100 percent organic wool and a cotton cover. It’s hand needle-tufted and made in the U.S. 

While this is not the most affordable mattress on the market—especially if you’re looking for one that’s plusher—the factors laid out here make its value clear. Plus with a full-year trial period, there’s more than enough time to decide if the cost matches the quality and your personal needs/preferences.

Best Value: Eco Terra Hybrid Latex Mattress

Trial period: 90 days | Warranty: 15 years | Firmness: Medium or medium-firm 

Why it stands out: While not a certified organic mattress, this one uses only natural materials and comes in two firmness options (medium and medium-firm). Plus there’s a lower-than-average price tag.

Eco Terra’s hybrid mattress comes in at a slightly lower price than its competitors—and that’s likely due to the fact that while the cotton and wool it uses are certified organic, its latex is not. The company also offers a noticeably shorter trial period (90 days) and warranty (15 years) than the other brands in this category. Otherwise, this mattress feels pretty comparable: no synthetic materials or toxic chemicals are used; the coils are individually wrapped (to help diminish motion transfer); it’s made in the U.S.; and you can even choose between medium and medium-firm for no extra cost. So if finding the most economical, natural-fiber mattress is your top priority, this one looks like a solid option.

Best Customizable: Naturepedic EOS Classic Organic Mattress

Trial period: 90 days | Warranty: 20 years | Firmness: Plush, medium, cushion firm, firm, or extra-firm

Why it stands out: The personalization. This mattress includes a latex layer, with firmness options ranging from plush to extra-firm, that can be customized for each side of the bed and swapped out as your needs change or to increase the life span of your mattress.

A front-runner in the world of natural-fiber mattresses, Naturepedic has been at it since 2003. It is a trusted source for quality organic mattresses—though all of that authority comes along with a higher price tag. Before you give into sticker shock, consider what you’re getting for the cost. The EOS mattress is available in five firmness options (ranging from plush to extra-firm); allows for an internal split so sleepers can choose their comfort layer; and has a zippered construction, which means you can switch out a layer if your preferences change or to extend the life of your mattress. And if you want to make that change within the first 90 days, you can do it for free.

Best Luxury: Birch Luxe Natural Mattress

Trial period: 100 days | Warranty: 25 years | Firmness: Medium-firm

Why it stands out: An upgrade on the brand’s original mattress, this option includes an added cashmere-wool layer that offers extra plushness and zoned lumbar coils designed to support the lower back.

The newest edition to Birch’s lineup, the Luxe mattress is an upgrade from its standard version and includes an extra top layer—a cushy blend of wool and cashmere—that adds to its plushness. The mattress’s layer of individually wrapped coils have targeted support in the lumbar region (to help reduce stress on your lower back), as well as extra support around the perimeter of the mattress (to help keep sleepers securely in bed). For purists, it must be noted that the latex used is not certified organic, and the fire-retardant covers include a blend of wool and rayon.

How We Chose These Products

I have spent months talking with family, friends, acquaintances, and experts. I’ve pored over brand stats and independent research. I’ve taken sleep quizzes and compared materials and certifications. After all this digging, here are my personal findings—and the ones I’ll be using to purchase a king-size mattress for myself.

My Shopping Checklist

Types of Mattresses

Common mattress types include innerspring (good for those who need back support), foam (good for side sleepers and those that have joint pain), and hybrid (a combo of spring and foam that provides both softness and support). If you’re a back and/or side sleeper like me, you’ll appreciate a hybrid mattress, which feels like the best of both worlds. It’s the category I focused on for my picks.

Level of Firmness

Mattress firmness levels range widely from extra-firm to plush—with many variations in between. Choosing the option that’s right for you is dependent on both your personal preferences, weight, and sleep orientation (side, back, stomach, or a combo).

Because my partner and I are both combination back and side sleepers and don’t love a superfirm mattress, I’m looking for something that’s medium to medium-firm, which tends to be a good middle ground and well suited for a large range of sleep profiles. Many of the mattresses I’ve found have options for all manner of firmness, including plush—but you might have to upgrade with a topper to get an extra-soft feel.

Motion Transfer

If you don’t sleep alone, motion transfer (the amount you’re able to feel your companion’s movements while sleeping beside them) is something to be aware of when choosing a mattress.   

Because I share a bed with my partner, motion isolation is a real need so we can both have a good night’s sleep. The latex toppers on hybrid mattresses help in this department as do pocket springs/individually wrapped coils.  

Removable and Washable Top Cover

To prolong the life of your mattress, it’s a good idea to invest in a mattress pad, like Coyuchi’s 100 percent organic cotton version. It can be easily removed and washed along with your bedding.  

Cooling Properties

Are you a hot sleeper? You’ve come to the right place. Natural-fiber beds are naturally temperature regulating and allow for good airflow, which can help keep you cool during the night.    

Delivery and Old Mattress Replacement

Free ground shipping is an industry standard. Many companies also offer an in-home or a white-glove delivery/setup option for an additional fee. Removal of an old mattress is a less common service, though it is an option from some companies, depending on your region.   

Warranty and Trial

These days nearly every mattress company offers a generous trial period (from 90 days to a full year) and warranties ranging from 15 years to even a lifetime. But be sure to read the fine print before buying. 

Ask Domino

Q: What’s the difference between a king-size mattress and a California king mattress?

The simplest way to put it: A standard king is wider than a California king by 4 inches, and a California king is longer than a standard king by 4 inches. So think about whether length or width is more important to you when making this decision—and the dimensions of your bedroom.

Q: Will any type of bed frame/base support a king-size mattress (ya know, as long as it’s big enough)?

Mattress support is important because you don’t want any sagging, which will inhibit effectiveness. My best advice is to check the weight of your mattress and be sure your frame is an appropriate base. 

Q: Do king-size mattresses from different brands differ in dimensions? 

While the length and width of mattresses are consistent (76 inches wide by 80 inches long for a king, and 72 inches wide by 84 inches long for a California king), the height of mattresses varies—ranging from 9 to 12 inches on average.  

Q: When buying sheets for a king-size mattress, is there anything special to keep in mind?

Standard king sheets are, generally, easier to find than California king sheets. So if you’d like to have more flexibility in the bedding department, a standard king-size mattress might be right for you. As noted above, the height of mattresses varies widely, so make sure the fitted sheets you’re purchasing are compatible with your mattress height. And don’t forget to consider any mattress pads or toppers you’re using as well. 

Q: What pillow size works best for a king-size mattress?    

Either two king-size pillows or three standard pillows will fit the width of a king mattress. 

The Last Word

After months of research, it’s become clear that the mattress market is overly saturated and not at all straightforward. In fact, it feels almost purposefully convoluted. But I parsed through the jargon to come to the conclusion that a natural-fiber hybrid mattress is what I need. 

Coming out on top of my best king-size mattress list is Avocado’s Green Mattress, which is certified organic and comprised of cotton, wool, latex, and individually wrapped springs. The company offers a generous one-year trial period and substantial warranty, so you can feel confident about your decision before committing. After all, with a product that’s so dependent on each person’s individual needs and preferences, testing it out firsthand (and for an extended amount of time) is the only real way to find out if it’s right for you. 

The other brands that made the list—Eco Terra, Naturepedic, and Birch—all have mattresses with similar constructions and materials, though firmness level, price, customization options, and trial periods/warranties vary slightly. Depending on your top priorities (perhaps that’s a split-king for partners with different sleep preferences; a more luxurious feel; or the most economical option available), if you’re in the market for a natural-fiber hybrid mattress, this lineup should include one that’s right for you.