As one of the originators of the bed-in-a-box movement, Casper has become the go-to brand for shoppers searching for a streamlined buying experience, quality construction, and a sound night’s sleep all in one convenient package. In this review, we’re focusing on the all-foam mattress that started it all for Casper, now reimagined and revamped based on a decade of real world usage and feedback to be aptly named “The One.” We’ll talk through the latest on performance, construction and cost, and bring you up to speed on all the upgrades to help determine if The One from Casper is meant for you.
| Pros | Cons |
|---|---|
| Recently revamped based on 10 years of customer feedback and testing | Firmer feel than most all-foam models may not suit side sleepers |
| Medium-firm feel appeals to back and stomach sleepers | Trial and warranty terms are shorter than some competitors |
| More responsive than most foam mattresses | |
| New open-cell foam design enhances breathability | |
| Excellent pressure relief from three layers of foam | |
| Superior motion isolation, particularly for couples | |
| Foams are CertiPUR-US® certified | |
| Completely fiberglass-free | |
| Free shipping within the contiguous United States | |
| 100-night sleep trial and 10-year warranty |
| Highlights | |
|---|---|
| Firmness: | Medium Firm |
| Sizes: | Twin, Twin XL, Full, Queen, King, Cal King, Split King |
| Materials: | Breathable Memory Foam |
| Design: | 3 layers of supportive open-cell foams to prevent overheating |
| Trial Period: | 100 days |
| Warranty: | 10-year limited warranty |
| Shipping: | Free shipping & returns |
About “The One” Premium Foam Mattress from Casper
The self-proclaimed “mattress that broke the internet,” The One is Casper’s signature premium all-foam mattress that’s been redesigned to be more breathable, more supportive and more dreamy than ever before, while still staying true to its roots with that classic Casper feel and affordable price that customers have come to expect. Featuring three layers of responsive, pressure-relieving foam for continuous support, plus an open-cell design to promote temperature regulation, all wrapped in a cozy cover for ultimate comfort, The One from Casper is even better than ever.
The Casper One Mattress Details
The team at Casper knows not to mess with a good thing, so when they wanted to give their all-foam flagship mattress an upgrade, they made sure to keep the coveted supportive feel that customers loved while revamping the materials and construction to address the feedback they’ve gotten through the years.
Materials & Construction
Layer 1: Cozy knit cover featuring a blend of polyester, polyethylene and Lycra spandex that promotes breathability and feels soft to the touch.
Layer 2: Breathable polyurethane foam with open-cell structure to increase airflow and help promote a cooler night’s sleep.
Layer 3: Supportive memory foam that provides the cradled feel that customers love while relieving pressure points.
Layer 4: High-density polyurethane foam for ultimate stability and durability to help prevent sinking or sagging.
Size Availability
The Casper One comes in a variety of sizes to meet your needs: Twin, Twin XL, Full, Queen, King, California King and Split King.
This all-foam model is 11 inches thick and can weigh between 47 and 100 pounds depending on the size you choose.
Firmness Level
While Casper offers an impressive selection of mattresses to meet nearly anyone’s firmness preferences, The One is specifically designed to deliver a medium-firm feel that suits a wide spectrum of sleepers. Slightly firmer feeling than their previous all-foam model, customers have described The Casper One as the perfect balance between comfort and support, but since it leans toward the firmer end of the scale, it may not be ideal for those who prefer a softer sleep surface or traditional memory foam feel.
Best Sleeper Styles
The all-foam construction of The Casper One is ideal for anyone who prefers the cradling comfort of memory foam mattresses, but its medium-firm feel makes it especially well suited to back and stomach sleepers who need more support, which has traditionally been lacking in foam mattresses. Side sleepers may find that The One is slightly too firm for their preferred sleep position.
The three layers of responsive foam provide continuous support to keep your neck, shoulders and hips properly aligned, while also providing just enough “sink” to keep you feeling comfortable and sleeping soundly all night long.
How The Casper One Performs
Pressure Relief
The triple-layer foam construction of The Casper One makes it a clear winner in this category for its ability to gently cradle the natural curve of your body, helping to relieve pressure points and prevent you from waking up sore and stressed.
Temperature Control
Unlike many all-foam mattresses that are known to trap heat, The One has an updated open-cell foam structure—known as Breathe Flex foam—to promote ultimate breathability and prevent your body from overheating and interrupting your sleep.
Motion Isolation
Foam mattresses are known for their superior ability to isolate motion, and the multi-layer foam design of The One makes it excel at absorbing movement, which is especially helpful when you’re sharing a bed with a partner who loves to toss and turn throughout the night.
Ease of Movement
Unlike traditional foam mattresses, The Casper One provides only a slight contour or “sinking” sensation while still keeping you supported near the surface, which makes it easy to switch positions as needed. This makes The One particularly appealing to couples who prefer a more responsive surface with just enough bounce for those intimate moments.
Edge Support
The One has enough edge support where sleepers don’t feel like they’re falling off the sides, but there is some give to be expected at the edges, especially when compared to the reinforced sides of hybrid or spring mattresses.
Durability
Casper uses high quality foams that are engineered for both comfort and longevity, backed by a “decade of durability” guarantee that assures they’ll provide lasting support for up to 10 years.
Off Gassing
While Casper asserts that their foams are all certified by the CertiPUR-US® program, some customers have noted a “new mattress” smell when first unboxing the Casper One, but confirm that the smell typically dissipates within the first few days. It’s a good idea to keep The One in a well ventilated area when you first open it to allow it time to expand and air out.
Pricing and Purchasing Process for the Casper One
On the front lines of revolutionizing the mattress buying experience, Casper has expanded from selling their mattresses exclusively online to also offering certain models at select major and local retail partners. They even have their own brick and mortar showrooms for buyers who prefer to see and feel a mattress before fully committing.
But buying direct can have its perks, including exclusive promotional pricing, special deals on complimentary accessories or add-ons (like pillows, mattress protectors, etc.), fast, free shipping and special financing options.
As Casper’s entry-level mattress model, The One is known for its superior construction and comfort for an affordable price. The Queen size of the Casper One typically retails for $999 on the brand’s website, but you can often find sitewide sales or special discounts, including a welcome offer when signing up to receive Casper emails.
Shipping & Delivery
When purchasing directly through Casper.com, customers can get free, no-contact delivery within the contiguous United States. Your Casper One mattress will typically arrive within two to eight business days after purchase via UPS. Keep an eye out during checkout for the option to sign up to receive text message updates about your order or even add a signature requirement.
The Casper One will be compressed and rolled tightly before being sealed in plastic and packed in a box that’s about the size of a mini fridge. There is no assembly required, but you will need to remove the packaging and allow between 24 to 48 hours for the all-foam mattress to fully expand.
If you prefer a helping hand, Casper does offer in-home delivery and set up for an additional fee, but it can take as long as two to four weeks to get scheduled.
Risk-Free Trials and Returns
Casper understands that buying a mattress online (or even in store) can come with a level of uncertainty. That’s why they offer a 100-night sleep trial. If you’re still not sure that The One is your “one” after an initial 30 day adjustment period, you can return the mattress and receive a full refund within 100 days after delivery. Returns within those first 100 days are free, and Casper will even arrange for the mattress to be picked up at no extra charge.
Warranty
Casper helps to protect your purchase by offering a 10-year limited warranty for The One mattress. This warranty covers manufacturer defects, but not accidental damage or normal wear and tear.
The Casper One Compared to the Competition
The bed-in-a-box market has multiplied in the last few decades, with new entries continuously promising to provide the best night’s sleep. Let’s see how Casper has continued to lead the pack:
Casper One vs. The Purple Mattress®
Shoppers often find themselves trying to decide between Casper and Purple mattresses, two top names in the foam mattress market. While Casper helped usher in the era of all-foam mattresses shipped to your door, Purple gained ground with a unique Gelflex Grid that helps to dissipate heat and provide an added layer of responsive support. Even with this special layer, the revamped Casper One is still almost two inches thicker than the Purple mattress, which means even more comfort and pressure relief, and now includes open-cell polyfoam for ultimate breathability and a cooler sleep. And while the companies offer similar sleep trials and both have 10 year warranties, the Casper One delivers the comfort and durability customers want at almost half the price of the Purple mattress, which makes it a clear winner when it comes to quality and value.
Casper One vs. Leesa
Both of these brands were at the forefront of the direct-to-consumer mattress industry, and their flagship all-foam options are still super popular with shoppers. After a recent revamp, the Casper One excels at providing temperature regulation thanks to its open-cell foam construction and breathability comfort cover. The Leesa Original is known to be a softer, squishier feel than the Casper One, which makes it lack the support needed for some back and stomach sleepers, or those over a certain body size. The Casper One is also priced lower than the Leesa Original mattress, making it a more attractive option for shoppers looking for the right balance of budget, comfort and quality.
The Bottom Line: Why We Love It
A leader of the mattress-in-a-box movement from the beginning, Casper knows how to deliver when it comes to comfort, convenience and cost. And with a fresh take on an old favorite, The One is still a preferred choice for shoppers who love the classic all-foam Casper feel but with a few added perks, all at a competitive price you won’t lose sleep over. The revamped Casper One takes cooling to the next level with open-cell foam for improved airflow and three supportive layers that work together to enhance pressure relief and keep your spine aligned. Firmer than some all-foam mattresses, The One still has just enough give combined with the right bit of bounce, making it easier to move around instead of feeling “stuck” in your mattress. With a 100-night sleep trial and 10-year warranty, you can feel confident that this popular Casper foam mattress is truly “the one” for you.
Casper Mattress FAQs
After a total revamp of their entire line in 2024, Casper has more options than ever to appeal to almost any kind of sleeper. From their flagship all-foam Casper One mattress to hybrid and max models, you can get just the right amount of comfort, support or cooling technology to suit your needs and budget. Casper provides access to helpful Sleep Specialists via phone, chat or email to provide a personalized recommendation based on your wishlist, or you can choose to take their interactive Mattress Quiz to help you narrow down your options online.
On average, a quality foam mattress should last between seven to 10 years. The Casper One is specifically engineered for durability with dense polyfoam and high-performing memory foam and is backed by a “decade of durability” 10-year limited warranty.
The Casper One is made up of high quality Polyurethane Foam and Viscoelastic Memory Foam, both of which are CertiPUR-US® certified. This means that they are made to be low VOC (volatile organic compound) and have met safety standards for indoor air quality, plus are free of ozone depleting chemicals, phthalates and heavy metals. The cover on the Casper One is also Oeko-tex Certified to be free from harmful chemicals. The One is designed and assembled in the United States and is completely free of fiberglass.
Featured In
Featured In
Methodology
The Consumer Rating Difference
Behind Our Best Mattress Ratings
We make finding the best mattress easy with expert reviews and rankings. Here’s the methodology behind our ratings:
Exhaustive Research
From the optimal firmness for side sleepers to the most effective cooling technology, we dive deep into the data to determine the best option for every kind of sleeper.
Mattress Reviews
No one knows the pros and cons of a mattress like the people sleeping on it. We read thousands of customer reviews to determine which mattresses customers like best.
Personal Experience
Our experts personally test out each top mattress, keeping in mind the features consumers care about most—like materials, design, cooling and firmness.
