The best king-size mattresses for 2025, tested and reviewed by CNET’s sleep experts

Our sleep experts have been testing mattresses, beds and accessories for years (a few have been tested for up to eight years). At this point, we have tested more than 300 mattresses from dozens of brands, from large as Purple and Tempur-Pedic to more niche companies like They sound and Airweave.

Our team is made up of bed testers with body weights and types, heights, genders and sleep preferences, which help us provide an overall assessment of each mattress from a multitude of points of view. Many mattresses are tested for long periods, ranging from a month or two up to five years.

We test king-size mattresses as we would with any other bed. When a new mattress arrives at ours testing facilityis subjected to a rigorous and practical test by each of our experts. We analyze specific features, including firmness, feel, temperature, motion isolation, edge support and other special features that the mattress may have.

Firmness

Firmness is rated numerically on a scale from 1 (the softest) to 10 (the firmest), and we use industry terms like soft or medium-firm to describe it. Our entire team takes turns evaluating and grading the firmness of each mattress, which allows us to make suggestions about the best-suited sleeping position and body type. After subjectively analyzing the firmness, we let our unique Mattress Smasher 9000 do its job and give us an objective firmness score.

Listen

Another subjective element that we review is the sensation of a mattress, separate from its firmness. Does it feel soft and responsive when you lie on it? Is it easy to change positions? Or does the dense memory foam conform around our bodies and hold our shape for a while? The mattress has a soft, plush superior cushion feelor is it more neutral? Can we hear coils or zoned support? We do our best to describe exactly what it feels like to lie on each bed to help you determine if it’s right for you without having to try them all yourself.

Read more: Why the foam in your mattress matters

Temperature

The temperature can be complicated to review when considering the personal preferences of each sleeper and the fact that many mattress brands exaggerate their beds. cooling capacity. When we test and review mattresses, we detail how hot or cool the mattress sleeps. Many external factors come into play here (such as climate and environment, bedding, pajamas, etc.), so we test beds in temperature-controlled rooms without sheets or bedding. Using our extensive knowledge and experience, we analyze their construction and materials and explain how they affect the temperature.

Motion isolation

Motion isolation is a term we use to describe how well the mattress dampens movement in its surface. It’s a particularly important feature for light sleepers or those who share a bed with a partner or pet. We test their motion isolation capabilities by having one expert lie on the bed while another stretches and changes positions. The second method is to put a glass of water on the edge, rolling it towards and away from it to see if it rises or falls.

Edge support

Edge support is not as important for king-size mattresses as it is for smaller sizes, such as queen or twin. Regardless, the edge support test allows us to assess how well it maintains its structure and support around the perimeter. We sit and lie on the shore to see how the bed responds. Does it collapse and give the feeling that we are walking, or is it sturdy and supportive? We also pushed on the edges with our fists to observe how the edge compresses under pressure.

Special functions

Some brands include special features in their mattresses, such as cooling covers for hot sleepers or zoned support for those with back pain. We test and review these additional features and determine which type of sleeper benefits you the most.