Over the years, CNET’s bed experts have developed a thorough and standardized methodology for testing every mattress that enters our mattress warehouse and testing facility. We have unboxed, rolled around on, tested, smashed, slept on, cut open and moved more mattresses than we can even count. We have mattress testers of all body sizes, genders, heights, weights and sleeping preferences so that we can test the beds from a wide variety of perspectives.

The primary characteristics we analyze and review include mattress construction and design, firmness, feel, temperature regulation, motion isolation, edge support and any other special features the bed may offer. We test each mattress from all sleeping positions, including side, back, stomach and combination. We take turns lying on and analyzing each bed’s firmness level and overall feel, comparing our deductions with the hundreds of other mattresses we have tested over the years.

Thanks to our one-of-a-kind Mattress Smasher 9000, developed by CNET’s brilliant lab technicians, mattress firmness can be examined subjectively and objectively. After placing the bed on the designated platform, we align the Smasher’s actuator arm in the middle of the bed and activate the corresponding software. The arm presses into the mattress with a preset amount of force, measuring how far down into the bed it travels using a system of lasers. It then provides an objective score on a scale of 1 to 10, with 10 being the firmest. We conduct at least five tests for each mattress, taking the average as the final ranking.

Sorted from softest to firmest, here’s how the Mattress Smasher scored the best memory foam mattresses on this list.

In our mattress facility, we test motion isolation, edge support and temperature. When we can, we zip the covers off or cut open the protective fire socks to further analyze the mattress construction inside. At this point in our sleep careers, we deeply understand how a bed’s construction informs every aspect of its performance, from durability to longevity to comfort.

There’s much more to our testing procedures than the simplified overview here, so if you want to learn more, this is a complete rundown of how CNET tests mattresses. CNET editors choose the products and services we write about based on editorial merit. When you buy through our links, we may get a commission.