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Our sleep experts have been rolling around and sleeping on different beds for years. Having tested approximately 350 mattresses from dozens of brands, our team has a good grasp on mattress firmness levels. Even with our strategic testing processes and extensive experience, our assessments have been solely subjective — until recently.
Brought to life by CNET Labs’ tech experts Bryan Adams, Jared Hannah and Steve Conaway, our proprietary Mattress Smasher 9000 machine offers an objective way to determine mattresses’ firmness levels.
This neat device has already smashed over 100 beds and counting. This number rises weekly as our experts continue to test the beds currently stored in our expansive mattress warehouse and the new mattresses we regularly receive to review.
Read more: We Use Tech to Test Beds: Say Hello to the Mattress Smasher 9000
Watch senior video producer Owen Poole explain how the Mattress Smasher works and why it changed the way we test beds.
The mattress-smashing process
Smashing each bed takes about thirty minutes. Moving the beds to and from our designated Mattress Smasher room and situating each on the platform takes some time. Once the bed is appropriately positioned and the machine is ready, we ensure the connected program numbers are correct, hit “start” and wait a few minutes for the smasher to work its magic and provide us with the objective firmness level.
This “magic” happens as the powerful actuator arm pushes its pressure-sensitive plate down into the mattress until it reaches a pre-determined amount of force, simulating body weight. The machine calculates the firmness based on the distance the arm and plate traveled into the mattress until they reached that force amount, traveling further (or deeper) into softer beds and not as far into firmer beds.
With our custom programming software, we can change the amount of force applied to the bed to simulate different body weights, allowing us to see how the firmness would feel for lighter and heavier body types.
We can adjust the actuator arm of the Mattress Smasher 9000 to test multiple areas of each bed.
We can also adjust the location of the actuator arm. Moving the actuator’s positioning over the bed enables us to test various areas of the mattress, which helps us determine whether the zoned support sections are actually softer or firmer, as the brands might claim.
Read more: Using Tech to Test Beds: Say Hello to the Mattress Smasher 9000
Mattress Smasher results, ranked by firmness
Firmness is rated on a scale of 1 to 10, with 1 being the softest and 10 the firmest.We use industry terms such as “medium-soft” or “true firm” to describe it. The firmness ratings provided by the Mattress Smasher are provided from the perspective of an average person weighing between 150 and 230 pounds, but we also test and discuss what the firmness might feel like for someone weighing above or below that range.
We smash each bed at least three times but often four or five (sometimes up to six or seven), taking the average of those scores to determine the final objective firmness level. Of the nearly 100 beds we’ve smashed to date, the average firmness level is 5.7, or just a hair above medium.
The graph below shows the firmness levels of the beds we’ve smashed with the Mattress Smasher 9000, organized from softest to firmest.
The Helix Sunset Luxe and Nectar Luxe Hybrid mattresses were the softest, with firmness levels of 2.1 and 2.2, respectively, according to the smasher. Soft scores like this are best suited for strict side sleepers who need the most pressure relief for the shoulders and hips possible.
The Mattress Smasher 9000 pushes the actuator arm into the bed.
To no one on our team’s surprise, the Airweave Nagomi mattress ranked the firmest of them all. It actually received a firmness level over 10 from the Mattress Smasher. This unique, ultrafirm bed is constructed with airy Airfiber blocks, making it suitable only for back sleepers seeking the most support possible.
Also unsurprising, the next firmest mattress was the extra-firm side of Plank Firm, landing at 9.8 out of 10, with Plank Firm Luxe close behind.
As we continue to test and smash beds, we anticipate that the average firmness level will stay between 5 and 6. Many mattress companies offer middle-of-the-road beds that can accommodate all sleeping positions and body types and offer a combination of pressure relief and support.
Read more: Best Firm Mattresses of 2025
What we’ve learned about mattress firmness
Not to toot our own horns, but we will… This new addition to our testing process has confirmed that our team of sleep experts is extremely accurate when evaluating and ranking a bed’s firmness level. Brands are also generally accurate in how they rank the firmness of their mattresses.
For the Bear Original mattress, the Mattress Smasher provided 7.6, 7.6 and 7.8 scores for a total average firmness ranking of 7.65 out of 10, while Bear clocks it at 7.1. While not exactly the same, it’s close, considering we have different methods and means of assessing and determining firmness — and both rankings mean the mattress lands around medium-firm.
We always test mattress firmness subjectively first, followed by its objective score.
It’s important to remember that even when technology is used to find the objective firmness level, firmness is still subjective at the end of the day. How one person perceives the firmness and feel of a bed may differ from another, depending on body type and weight. Our sleep team consists of members of different body types, weights and genders, allowing us to test each mattress from various perspectives and provide an all-encompassing review of the bed.
Zoned support
Many mattresses feature zoned support, meaning different firmness levels throughout the bed provide support and pressure relief where your body needs it most. It’s intended to help keep the spine neutrally aligned throughout the night.
This is accomplished by altering the bed’s construction, typically by having slightly firmer foam or a layer of individually wrapped coils in the center for enhanced support for your torso and hips. The outer thirds are often slightly softer to provide pressure relief for your head and shoulders. An example is the Saatva Classic, which features an additional layer of thin memory foam in the center third of the bed.
The Mattress Smasher 9000 has proven that the brands’ claims of zoned support are generally true and accurate. Even if we can’t necessarily feel the zoned support while lying on certain beds, the Mattress Smasher can confirm that different firmness levels are present.
The Saatva Rx is a prime example of this. Specifically designed for those with chronic back and joint pain, it features patented Lumbar Zone Technology. This technology provides more support in the center third of the mattress, aiming to keep your spine neutrally aligned. We moved the actuator to test each third of the mattress and confirmed this to be true — the inside ranked around 6.1 out of 10, and the outer thirds were slightly softer, around 5.4 out of 10.
With the Mattress Smasher, we can test the firmness of various areas in mattresses with zoned support, like the Saatva Rx.
Interesting discoveries we had during testing
Like any technology, the Mattress Smasher 9000 is not always 100% accurate. It might occasionally rank a bed higher or lower than we know it to be, and we always use our best judgment and discretion to determine why and whether the score is off from what its firmness rating truly is. We’ve encountered a few interesting realizations as we continue to work out any kinks with the Mattress Smasher.
Mattresses with super unique construction, such as the Layla Hybrid, can sometimes throw off the firmness score provided by the smasher. We always investigate to determine the cause, and in this case, since the Layla Hybrid is flippable, the base of the mattress is soft when the firm side is up, which resulted in a few funky scores.
We’ve also found that beds with soft top comfort layers or cushioning pillow tops tend to score softer than they are. This is because the actuator arm of the Mattress Smasher does not press down as far into the mattress layers as in a bed without a pillow top, causing it to provide a score that’s softer than it would feel for a real person lying on the whole bed.
An example of this is the Titan Plus Luxe. In our testing, we found this bed to be around medium-firm, while the Mattress Smasher consistently gave us lower scores between 3 and 4, which would be medium-soft. We know this is because of the soft quilted gel foam top on the Titan Plus Luxe.
The Titan Plus Luxe has a thick pillow top that slightly affected the Mattress Smasher’s scoring.
Temperature affects the Mattress Smasher results
When the bed (particularly one with memory foam) is cold from being outside in cool weather or a room with no heat, it will score higher (firmer). The bed can become more rigid when it reaches a certain threshold, as memory foam is sensitive to temperature fluctuations. The foam molecules become more tightly packed when cold, resulting in a harder feel. Typically, memory foam beds feel best between 68 and 72 degrees F.
Read more: The Foam in Your Mattress Matters. Here’s How It’s Made
Our sleep team knows this well. We are patient when unboxing memory foam mattresses from the cold delivery truck in the winter, as they’re much more rigid and firm than they will be once they’ve had a chance to warm up and properly inflate. It’s the same when lying on a memory foam bed in a cold room — it takes extra time for your body heat to warm before the foam begins to respond appropriately, sinking and contouring around you.
The building where our mattress warehouse is situated recently encountered heating issues, which meant there was no heat in the rooms where we store, film and smash beds. The resulting cooler room temperatures affected the Mattress Smasher scores for memory foam mattresses, causing them to rank higher than they should.
Watch us unbox the extremely cold Casper Snow Max.
Why we use technology to test beds
Our sleep experts always provide in-depth descriptions of a bed’s firmness and feel in our reviews to help you decide if it’s the right bed for you. These qualities are largely subjective. How a bed feels from person to person will differ. We take turns lying on and dissecting the mattress’s construction, collecting opinions on the firmness level from multiple CNET sleep experts with varying body types and preferred sleeping positions because it’s critical to test and review this characteristic from a wide range of perspectives.
Until CNET Labs created the Mattress Smasher 9000, this was the only way we could test a bed’s firmness. Now, having an objective way to test and determine firmness supplements our expert assessments and makes our reviews even more precise by providing entirely unbiased data. As a dedicated member of CNET’s sleep team, the Mattress Smasher 9000 will continue to test and analyze beds alongside the rest of us for the foreseeable future.
Read more: How CNET’s Sleep Experts Test Mattresses
