Can Two Adults Sleep on a Twin Bed?

Sharing a twin bed with another adult isn't recommended. A queen bed is the most common choice for couples, but other options are available.

Two adults might be able to lie down next to each other on a twin bed, stretch out, cuddle, or even doze off. But can two adults sleep on a twin bed all night comfortably without waking up with stiff necks in the morning? In most cases, the answer is no.

Learn why squeezing in with another full-grown human may negatively affect your sleep quality, comfort, or even your relationship. After going over the downsides of sharing a twin bed, we'll touch on the few instances when it might be acceptable and more practical bed size options to consider.

Twin Bed Dimensions at a Glance   

A standard twin mattress is 38 x 75 inches. Twin beds are not only the narrowest option, but since they're mostly meant for kids, they're also shorter than queens, standard kings, and even twin XL beds by 5 inches.

It varies, but a standard twin mattress (let alone the bed frame) is typically designed to support no more than 300 pounds.¹ So, if the two sleepers' combined weight is higher than the capacity, the mattress won't offer proper support and may break down quicker than it would with just one sleeper.

Space per Sleeper

If you were to split a twin mattress right down the middle, you'd be left with just 19 inches of width per person—much less than a single adult sleeper normally enjoys (and needs). Most people require a bit more space for their shoulders, comfy pillow placement, and the ability to change positions during the night.¹

Shoulder-Width Reality Check

The average width of adult male shoulders is 16 inches. For adult females, it's 14 inches.² If two people were to sleep on their backs, shoulder to shoulder, this would leave barely any wiggle room. And even if you doze on your sides, you have to account for the angle of your legs, head space, and—again—room to roll over or switch positions. The point is, you're almost guaranteed to overlap somewhere when sharing a twin bed with another adult.

Sleep Quality and Health Impacts

What happens when you don't have enough space on a mattress? You may not be getting the quality shut-eye you need. Call us sleep nerds, but this is something you definitely don't want to skimp on. If you’ve ever wondered, “Should I get a bigger bed?”, especially if you’re sharing one, you probably should.

A twin mattress might work for one adult, depending on their height. But when it comes to sharing a bed with a partner, research has linked larger mattress sizes with longer overall sleep times, increased REM (rapid eye movement) and deep sleep, and a shorter time to fall asleep.³ Win-win-win.

Movement-Related Disturbances

Though some research has claimed that bed partners account for 50% of nighttime awakenings, more recent studies show that sleeping with a partner may actually help people sleep better.^4,5,6

Of course, there are exceptions. Namely, when sleeping with another person means there's not enough room for you, and limited space means you feel their every toss and turn.⁷ In most cases, sharing a twin bed isn't better for your sleep simply because there's not enough space for two.

Long-Term Sleep Deprivation Risks

Getting poor sleep one night because you bunked up with someone might not be that big of a deal. Still, even just a night or two (or an entire week) without quality shut-eye can result in elevated stress, anxiety, and difficulty focusing.⁸

Long-term sleep deprivation can be even worse for your health, affecting everything from the immune system and hormones to appetite and inflammation. Chronic sleep loss might raise the risk for high blood pressure, high cholesterol, weight gain, and type 2 diabetes while compounding all the short-term effects.⁸

Weight Capacity and Mattress Longevity

As mentioned, twin size mattresses really aren't designed to accommodate the weight of two people, let alone two adults. When the total weight surpasses 300 pounds (or whatever the weight capacity is for the mattress you're sleeping on), it can strain the springs, break down the foam, lead to mattress sagging or lumpy areas, and ultimately shorten the lifespan of the mattress.^9<7sup>

When Sharing a Twin Might Be Okay

Is it ever okay to share a twin bed with another adult? Though it's not recommended for all the reasons listed above, it's your choice in the end (you might know of a college couple or two who bunked up in the dorms for a stint).

Here's when it might be fine to make an exception.

Short-Term Stays and Travel

Sleeping over at someone else's home, traveling as a group with shared lodging, or staying at a hostel, for example, could be instances where it's okay to share a twin bed. But ideally, it won't be more than a night or two.

This type of sleeping arrangement will work best if each person is short or otherwise petite and a relatively deep sleeper. Even better if both people really enjoy cuddling..

Emergency or Budget Constraints

There could also be a temporary scenario involving budget constraints or while waiting for a larger bed to be delivered. In that case, short-term bed sharing might work.

Having said that, even having one person sleep on a sofa or air mattress could be better than two adults sleeping in a twin bed—even if it's hard to imagine not co-sleeping with a romantic partner while staying under the same roof.

Tips If You Must Share a Twin Temporarily

If sharing a twin-size bed with another adult is unavoidable, you can make the most of it by placing a foam mattress topper on the surface to improve motion isolation and provide extra comfort. Thinner pillows might help you both feel like you have more head space, too.

Another thing that could help is aiming to go to sleep and wake up around the same time as each other. That way, one partner won't disturb the other when getting in and out of bed (this can be beneficial when sharing a larger bed as well).¹⁰

Better Mattress Sizes for Couples

Since twin beds are the smallest of the standard sizes, any other size would be an improvement. Still, what is the best bed size for couples? Some mattress sizes are more ideal than others.

Full/Double (54" × 75")

A full-size mattress (sometimes called a double) is 54 x 75 inches. So, it's the same length as a twin but 16 inches wider, offering each sleeper 27 inches of room. While this bed size is more spacious, it's considered the minimum feasible size for two adults. Also, taller people will need a longer bed.

Queen (60" × 80")

A queen mattress measures 60 x 80 inches. It's not only 22 inches wider than a twin (giving each person 30 inches of space) but also 5 inches longer. This bed size is the most common for adult sleepers, 61% of whom sleep with a significant other.¹¹

Queen beds tend to be the most practical option for many people in terms of price, availability, and footprint, as they fit in most bedrooms. Even if you don't share a home with your partner and only have them sleep over a night or two a week, a queen bed will ensure you always have enough space.

King (76" × 80")

A king mattress is 76 x 80 inches, so it's double the width of a twin and 5 inches longer. This offers couples maximum personal space (36 inches widthwise per person), with plenty of room to spread out, snuggle up, roll over, and switch sleeping positions throughout the night.

If you have the available square footage in your bedroom, it could be worth investing in a king mattress. A king bed can also be a good option for larger bodies and restless sleepers who want to be mindful of not waking their partners.

California King (72" × 84")

Despite common misconception, a California king mattress isn't bigger than a standard king—it's a variation of a king. Measuring 72 x 84 inches, this mattress size is 34 inches wider than a twin and offers each sleeper 36 inches of space.

If you’re weighing California king vs king, the main difference comes down to dimensions:  a Cal king is actually 4 inches narrower than a regular king, it offers 4 additional inches lengthwise. This makes it a good option for very tall adults (6-foot-4 and over) and for some long, narrow bedroom layouts. Otherwise, a standard king might be better in terms of space for a couple.

Casper Mattresses—Size Up for Real Rest

If you're ready to size up your sleeping arrangement, Casper has you covered with the essentials. We have full, queen, king, and California king mattresses with motion isolation and zoned support to accommodate adult sleepers and couples with varying needs. You might even consider the pros and cons of a split king, which is a king-size setup made of two separate twin XL mattresses placed side by side to equal the dimensions of a standard king.

Great sleep shouldn't be a squeeze, so give you and your partner room to breathe and space to move. Plus, when you order from Casper, you can try a mattress risk-free for 100 nights. If you're not totally in love with your new mattress within the trial window, we'll take it back, no questions asked.

Sources:

1. Nursing Research. What Bed Size Does a Patient Need? The Relationship Between Body Mass Index and Space Required to Turn in Bed. https://pmc.ncbi.nlm.nih.gov/articles/PMC5671795/
2. U.S. Department of Health and Human Services. Anthropometric Reference Data for Children and Adults: United States. https://www.cdc.gov/nchs/data/series/sr_11/sr11_249.pdf
3. Sleep Medicine. The association between mattress size and objectively measured sleep in 8,214 users with bed partners. https://www.sciencedirect.com/science/article/pii/S138994572200449X
4. BBC News. Bed sharing 'bad for your health'. http://news.bbc.co.uk/2/hi/health/8245578.stm
5. Sleep Medicine Reviews. The association between couple relationships and sleep: A systematic review and meta-analysis. https://www.sciencedirect.com/science/article/abs/pii/S1087079224001229
6. Frontiers in Psychology. Bed-Sharing in Couples Is Associated With Increased and Stabilized REM Sleep and Sleep-Stage Synchronization. https://pmc.ncbi.nlm.nih.gov/articles/PMC7330166/
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8. Nature and Science of Sleep. Short- and long-term health consequences of sleep disruption. https://pmc.ncbi.nlm.nih.gov/articles/PMC5449130/
9. Journal of Manipulative and Physiological Therapeutics. Mattress Coil Spring Fatigue and Weight-Bearing Support: Comparison of Weight-Bearing and Non–Weight-Bearing Springs. https://www.sciencedirect.com/science/article/abs/pii/S0161475422001166
10. Sleep Health. Vulnerability and resistance to sleep disruption by a partner: A study of bed-sharing couples. https://www.sciencedirect.com/science/article/abs/pii/S2352721819302670
11. Sleep Medicine Reviews. Marital quality and the marital bed: Examining the covariation between relationship quality and sleep. https://pmc.ncbi.nlm.nih.gov/articles/PMC2644899/
12. Better Sleep Council. Mattress Sizes: Fit for a King, but a King Might Not Fit. https://bettersleep.org/mattress-sizes/
13. Better Sleep Council. Sleep and Partners Research 2023. https://bettersleep.org/research/sleep-and-partners-research-2023/