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Our team of bed experts tests each mattress that comes into our mattress warehouse and sleep lab. We test all sleeping positions: side, back, stomach and combination on each bed. We also test for motion isolation, edge support, temperature, comfort and more. As for firmness, our team has two ways of testing how firm a bed feels. First, we rate the perceived firmness and feel, converse with other teammates and compare the bed’s firmness to the other 300 we have tested. Then, we objectively measure a bed’s firmness with a proprietary machine dubbed the Mattress Smasher 9000. Our lab technicians developed this device and the corresponding software in-house. It presses into the middle of the mattress and scores each bed on a scale of 1 to 10, with 10 being the firmest and 1 being the softest. 

Here's the data we learned testing the best memory foam mattresses with our Mattress Smasher 9000. Sorted from the softest beds to the firmest, here's how the mattresses scored on our firmness scale.

When testing, we sleep on beds, trying out all three different sleeping positions: side, back, stomach and combination. We also test for motion isolation, edge support, temperature, comfort and more. We have even cut open a few mattresses to see what the construction is like on the inside. 

The best memory foam mattresses are comfortable to switch positions in, offer a pressure-relieving feel, isolate motion and are very accommodating for different sleeping positions. We also take durability into account, considering whether it will be long-lasting for every body type. 

Find out more on how we test mattresses.