I've been sleeping on the Casper One for a week and it's making me love firmer memory foam mattresses

A queen-size Casper One Mattress on a black bed frame atop an ornate rug with shades of red and green. A black and white dog is laying on top of the mattress.
(Image credit: Future/Sophia Carlisle)

Since this hands-on was written our sleep team has had a chance to complete a full review of the Casper One Mattress. You can read all our thoughts on the performance, comfort and support in our Casper One mattress review.

The Casper One Mattress (also known as The One) is billed as an affordable memory foam mattress that delivers a firmer feel with sufficient pressure relief. As a fan of plush beds, I was hesitant to try the Casper One Mattress, but after one week of testing it, I find it so comfortable that I'm reconsidering my sleep preferences.

Like its predecessor the Casper Original mattress, The One consists of three layers of foam. However, The One features an Align Memory Foam for deeper pressure relief and swaps out the Zoned Support Foam found in The Original. The One also has a firmer feel than the medium-plush Casper Original and also costs up to $300 less.

Casper The One: Quick specs

Type: Memory foam
Materials: Memory foam, polyfoams
Firmness (1-10): Medium firm (7)
Height: 11”
Trial period: 100 nights
Warranty: 10 years
Price: from $749 at Casper

So does the Casper One have what it takes to contend with the best mattresses we've tested this year? I'm still in the process of putting together a comprehensive review with full testing data, but The One has made a strong first impression. Keep reading to find out why I think the Casper One Mattress delivers on its promises after just one week of testing.

Now is a great time to upgrade your mattress too thanks to the upcoming Presidents' Day mattress sales. The Casper One is usually on sale and right now its 20% off, with a queen priced $799 (was $999) in the Casper mattress sale, placing it at the lower end of the mid-range market.

Casper One Mattress: Price & trial

  • Casper's entry-level memory foam mattress
  • Regular discounts cut 20% to 30% off MSRP
  • Comes with a 100-night trial and a 10-year warranty

Casper is behind some of the best mattresses in a box money can buy and The One is the brand's entry-level all-foam mattress. A queen retails for $999; however, Casper mattress sales regularly occur throughout the year, so you'll never have to pay full price. Discounts range from 20% to 30% off, with larger markdowns reserved for major holidays.

Here are the current retail prices for all sizes of the Casper One Mattress:

  • Twin MSRP: $749
  • Twin XL MSRP: $799
  • Full MSRP: $899
  • Queen MSRP: $999
  • King MSRP: $1,399
  • California King MSRP: $1,399
  • Split King MSRP: $1,498

All Casper mattresses come with a 100-night at-home trial and a 10-year warranty. Those are both within the industry average and decent perks for a mid-range mattress such as The One. Shipping and returns are free.

Casper One Mattress: $749$599 at Casper

Casper One Mattress: from $749 $599 at Casper
The current Casper sale cuts 20% off all mattresses. We've seen as much as 30% off The One in the best monthly mattress sales, but lower MSRPs are yielding better prices now. A queen is now $799 (was $999), which makes it competitively priced among this year's best memory foam mattresses for different budgets.

Unboxing my Casper One Mattress

  • Arrives vacuum-sealed in a box, but expands quickly
  • Some off-gassing, but minor compared to other brands
  • Comfortable enough to sleep on the first night

A queen-size Casper One Mattress arrived at my home rolled and boxed up. I had to wait for it to expand after opening. It inflated surprisingly quickly, so I was able to sleep on it the first night. I did notice a bit of an off-gassing smell the first few days, but it was minor compared to other mattresses I’ve slept on.

Unboxing a mattress is convenient if you don’t want to deal with the hassle of delivery or moving a large bed yourself. However, I would recommend you have someone else on hand to assist with setup. For a woman of average height and strength, this was a significant challenge to unbox and set up, in part because of how quickly the mattress expanded to size. Once the Casper One expanded, it was difficult to arrange on my bed frame due to the weight (a queen weighs 76lbs.)

My first week sleeping on the Casper One Mattress

Night 1: Firmer than expected

Casper rates The One as a medium to firm mattress. I agree — with a caveat that it’s definitely on the firmer side. The One took some getting used to, as its initial firmness was quite different from my usual mattress, which is medium to soft. I’m primarily a side sleeper but did experiment with back and stomach sleeping on The One.

From the first night, I found sleeping on my back and stomach to be very comfortable. My weight felt evenly distributed, and I was pleased by the pressure relief, specifically for my lower back. If you're looking for the best Casper mattress for back and stomach sleeping right now, The One is a great choice.

Side sleeping took another night or two to find my groove, but I adjusted relatively quickly. The Casper One has just enough give to still allow sinkage without dipping too much. Side sleepers who like a plusher feel may still experience a bit of softness, but it may not match the comfort of a proper mattress for side sleepers.

A man in a grey t-shirt and jeans lying on his back with his arms behind his head on the Casper One Mattress in his bedroom, with his black and white dog sitting on the other side of the bed, contentedly.

The medium-firm Casper One Mattress is an excellent choice for back sleepers. (Image credit: Future/Sophia Carlisle)

Nights 2-7: Full of pleasant surprises

After only a few days of testing, I noticed a difference in how stiff I felt waking up. A firm mattress might not be my usual go-to, but I’ve felt such a tangible change in how I feel after sleeping on The One, I'm considering making the switch to a firmer bed going forward. (Considering my sleep preferences, that’s about the best endorsement I could give.)

Side sleeping is certainly comfortable on this mattress (as I learned during testing), but I would primarily recommend it for back and stomach sleepers who enjoy a lot of pressure relief. My partner is a committed back sleeper, and at the end of our trial period, he was quite sad to see this memory foam mattress go.

A kettlebell (weight unknown) sinking into the center of the Casper One Mattress to objectively test its level of pressure relief.

Despite its firmer feel, the Casper One Mattress delivers ample pressure relief. (Image credit: Future/Sophia Carlisle)

The comfort of the Casper One made our sleep trial a breeze, but we were surprised by its excellent motion isolation. My partner and I wake up at different hours, and I’m generally restless at night, so I typically stir each time he moves or gets out of bed. The Casper One isolated movement so well on my partner’s side of the bed that I never woke up when he rose for work in the morning — a very happy first for me.

We both noted that edge support was a bit weak, with the sides of the bed dipping under direct pressure from our hands and testing materials, but this would only be a consideration for someone needing strong edge support. As it stands, this isn’t a necessity for my partner and me, so it wasn’t a big factor in our overall opinion of the mattress. That said, hybrid mattresses are usually a better choice for strong edges than all-foam beds.

I tested this mattress in January, so overheating wasn’t a huge concern. However, I did crank the heat in my apartment on a few especially chilly days and noticed a slight uptick in temperature on the bed. Neither I nor my partner were particularly bothered by this, but the knit cover encasing the mattress might make it a little toasty on hot nights. If you tend to sleep warm at all points of the year or live in a warmer climate, consider a specialized cooling mattress like the Casper Snow.

Casper One Mattress: My early thoughts

A queen-size Casper One Memory Foam Mattress, shown from the foot of the bed with the brand's purple and white logo on the right side. The mattress is on a black bed frame that's on top of an ornate bedroom rug with shades of red and green.

(Image credit: Future/Sophia Carlisle)

After a week of testing, I can confidently say the Casper One Mattress exceeded my expectations. I was pleased by its balanced feel and exceptional motion isolation, and the 11" height created a profile that was just right for my bedroom. If you're looking for a great mattress for couples, the Casper One is sure to make you and your partner happy.

A week may not be a long time, but as a former devoted plush bed sleeper, I’m impressed by how quickly The One won me over with its combo of relief and support. But you don't have to rush to a decision, as Casper offers a 100-night risk-free trial. Purchasing a bed that will make or break your sleep is a big deal, so I like that you can give this mattress a go for a few months before totally committing.

For the price, The Casper One is a solid investment and is a notable upgrade from its predecessor, the Casper Original Mattress. Whether you’re thinking of switching models or buying a Casper mattress for the first time, I don’t think you’ll be disappointed by The One, even if your typical preference is a softer mattress.

Sophia Carlisle
Freelance journalist

Sophia Carlisle is a writer and editor with a soft spot for pets and lifestyle topics. She’s tested and reviewed pet, home, and sleep products for various mainstream publications, including some of the latest mattresses for Tom's Guide. Sophia currently lives in Minnesota with her rescue pit mix Lyla, who also enjoys helping test products. 

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