Mattress Sizes and Dimensions Guide

Whether you’re remodeling the bedroom or upgrading your mattress, it’s helpful to determine the best mattress size for your space. The number of options in today’s market can be overwhelming.

What’s the difference between a full and a queen? How big is a California king? This comprehensive mattress dimension guide answers all of those questions and more.

Once you’ve learned a little about today’s mattress sizes, we’ll help you choose the best mattress for your home and lifestyle.

Mattress Dimensions Guide

Standard mattress sizes, dimensions, and names vary from country to country. Two mattresses of the same size may even have slight variations by manufacturer. If you live in the U.S., these mattress dimensions are considered standard across brands. In general, standard mattress depths range from about 9-13 inches when the high contour is considered.

Remember, widths can vary between the U.K. and the United States, so check the dimensions before you order those fancy European sheets online. According to the International Sleep Products Association, most beds are 74 or 80 inches long in the U.S. Meanwhile, the length is typically 75 or 78 inches in the U.K. It seems minimal but makes a big difference when considering the fit of a frame and sheets.

Below, you find the standard mattress dimensions for the U.S. and Canada along with helpful information and common misconceptions about these mattress sizes. We’ve also included a handy room guide to know what size bed your room can accommodate.

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Mattress Size Chart

When comparing these mattress sizes, it’s important to look beyond just the numbers.

Think about how these dimensions translate into real-world comfort—especially for couples, growing kids, or tall individuals who need that extra length.

This table is especially useful when deciding what fits best in your space while ensuring comfort based on body type and sleep habits.

a. Full Size Crib Mattress

Crib mattress dimensions: 27.25 inches by 51.25 inches

Minimum recommended room size: 7 by 10 feet

Since safety is a top priority for cribs, the size of cribs and mattresses is regulated by the federal government. A full size crib mattress must be at least 27 1/4 inches wide and 51 1/4 inches long. The mattress cannot be more than 6 inches thick.

A crib, of course, won’t take up much room. But it’s important to keep in mind most building codes require a bedroom to measure at least 70 square feet, like a 7-by-10-foot room. The ceiling height must also reach 7 feet, 6 inches.

You can certainly create a cozy nursery in an attic room or something comparable to fit a crib and a comfy chair. However, these smaller rooms won’t be considered bedrooms when it comes to a real estate listing. No matter what, make sure there is a planned fire escape route if you are squeezing things in tightly.

In addition to federal size regulations, crib mattresses must fit snugly in the crib frame to reduce the risk of entrapment or suffocation—there should be no more than two fingers’ width between the mattress and the crib sides.

When evaluating crib mattress dimensions, also consider firmness. Pediatric guidelines recommend a firm, supportive surface to promote safe sleep for infants and reduce the risk of SIDS (sudden infant death syndrome). This is why many crib mattresses are dual-sided—with a firmer infant side and a softer toddler side.

b. Twin Size Bed

Twin size bed dimensions: 38 by 75 inches

Minimum recommended room size: 7 by 10 feet

The humble twin size mattress is the smallest of the standard bed sizes. At just 38 by 75 inches long, the twin is considered the minimum size needed for the average adult to sleep comfortably.

Twin mattresses are not the best option for those over six feet tall. However, since the majority of the world is under six feet, twin beds work for most sleepers.

Twin size beds are fantastic for smaller rooms. College dorm rooms are the perfect spot for the twin size bed, as are studio apartments. Twins also work well for multipurpose guest rooms or rooms with multiple beds in them. Think kids’ rooms or bunk beds.

Twin size beds are also a highly convenient option for those who like to move a lot. Most bed sizes take two people to lift, but twin size beds of just about any material are usually easy for one person to lift and maneuver.

SEE ALSO: Twin vs. Full — What’s the Difference?

c. Twin XL Size Bed

Twin XL size bed dimensions: 38 by 80 inches

Minimum recommended room size: 9 by 10 feet

The twin XL size mattress is the same width as the regular twin. But it adds 5 inches of length for a dimension total of 38 by 80 inches. This makes the twin XL as long as the queen and king size mattresses.

The twin XL mattress is still a compact bed that fits in just about all the spaces that a regular twin can fit into. But the twin XL is long enough to accommodate most people, no matter their height.

That means the twin XL needs a longer room than the twin. Keep in mind that the general rule is you need two feet of space around three sides of your bed. Since the twin XL is over 6.5 feet long, you’ll need 10 feet of length to accommodate it. More if you plan on using bedroom furniture.

Don’t let that deter you, though. The twin XL can still fit right into the same places a regular twin can. That includes studio apartments, multipurpose guest rooms, and bunk beds.

The twin XL is also commonly found in college dormitories across the U.S., where it’s often the standard mattress size used by universities to accommodate a range of student heights.

It’s also a popular choice for pairing in split king beds—two twin XLs combined allow each partner to choose their own mattress type and firmness while sharing the same frame.

d. Full Size Bed

Full size bed dimensions: 54 by 75 inches

Minimum recommended room size: 9 by 10 feet

The full size mattress (also called the double bed) is 54 by 75 inches. That makes it perfect for sleepers under six feet tall who like to have a little extra wiggle room to toss and turn.

Contrary to popular belief, the full size bed is not the best bed for couples. The name “double bed” might lead you to believe this bed can accommodate two sleepers. But in reality, the double bed only offers each of two sleepers the same amount of sleeping surface as a baby’s crib. That’s not exactly comfortable for two adults.

This means the full size mattress is a better fit for single adult sleepers who want more width to spread out but don’t have the room for the longer queen bed.

Just like the twin bed, the dimensions of a full mattress can comfortably accommodate the numerical majority of sleepers. But it isn’t a great fit for those over six feet tall.

Full beds also work well in teen bedrooms or studio apartments where space is tight but a more generous sleeping surface is desired compared to a twin.

When comparing mattress sizes, full mattresses tend to hit the sweet spot between space-saving and comfort for solo sleepers—especially those who want enough room to move around without upgrading to a queen.

SEE ALSO: Twin vs. Full vs. Queen: What’s The Difference?

e. Queen Size Bed

Queen size bed dimensions: 60 by 80 inches

Minimum recommended room size: 10 by 10 feet

The queen size mattress is the most popular bed size on the market—and with good reason. The 60 by 80-inch queen fits in just about any room and can accommodate just about any sleeper. At 80 inches long, the queen can comfortably sleep people of almost any height. And at 60 inches wide, it can offer most couples enough width to sleep comfortably.

The queen size bed can also fit in just about any bedroom. Unlike king and California king beds, queens can go in guest rooms and smaller master bedrooms.

Queens are also the cheapest bed size that can accommodate couples. Cal kings and kings will cost you a pretty penny. But quality queens can go for as little as a few hundred dollars.

Queen beds also offer enough room for a child or pet to join parents without feeling cramped, which is why many families favor this size in shared sleeping situations.

If you’re deciding between mattress dimensions for a couple or co-sleeping needs, the queen often provides the ideal compromise between price, space, and practicality.

SEE ALSO: King Vs. Queen Mattress — What’s the Difference?

f. King Size Bed

King size bed dimensions: 76 by 80 inches

Minimum recommended room size: 12 by 12 feet

King size mattresses are 76 by 80 inches. They come in at a cool 6,080 square inches, making them the largest standard bed size by total surface area.

These beds were literally designed with couples in mind. King size beds are the same size as two twin XL beds put together. That means they offer the same sleeping width as a twin and the same length as a queen. So they’re perfect for couples and taller sleepers alike.

King size beds might be designed for two sleepers, but that doesn’t make them for everyone. If you have a smaller bedroom, kings may not be for you.

Technically, you could stuff a king into a room as small as 10 by 9 feet. However, if you want comfortable wiggle room and space for furniture, it’s better to have a bedroom of 10 by 12 or 12 by 12 feet.

In addition to spacious dimensions, king size beds are ideal for light sleepers who are easily disturbed by partner movement. The extra width significantly reduces motion transfer and offers individualized sleeping space.

King mattresses are also preferred in luxury bedroom setups and master suites, often paired with upholstered headboards or statement bed frames to complete the look.

SEE ALSO: King vs. Split King — What’s the Difference?

g. California King Size Bed

California king size bed dimensions: 72 by 84 inches

Minimum recommended room size: 12 by 12 feet

The California king bed was originally designed for the huge bedrooms found in opulent mansions in Southern California. These 72 by 84-inch beds fill out even the largest master bedrooms.

The California king does need a large bedroom. It’s a full 7 feet long by 6 feet wide. That means these beds will only fit in a room of at least 10 by 12 feet. A room this size will accommodate a California king size mattress and some bedroom furniture, though a 12 by 12-foot room is best for a Cal king.

California kings aren’t only for huge bedrooms. At 84 inches long, they’re also great for sleepers well over 6 feet tall. If you’re 6 foot 4 inches or more, California kings may just be the only standard mattress size on which you can really sleep comfortably.

So couples or even single sleepers who need an extra-long bed or a bed that can fill out their huge master bedrooms should consider a California king.

If you’re choosing between standard mattress dimensions and your height is the deciding factor, the California king offers the most legroom of any mattress available.

Despite being narrower than a traditional king, the California king’s extended length makes it ideal for athletes, tall sleepers, or those who sleep with large pets at the foot of the bed.

Mattress Size Comparison Chart

This side-by-side comparison helps simplify the decision-making process for those comparing mattress sizes and dimensions based on space, use, and sleep needs.

SEE ALSO: King vs. California King: What’s the Difference?

Quick Room-Size Guide

Below, we’ve listed the standard mattress sizes and the minimum bedroom size needed to fit each bed.

Interior designers typically recommend leaving at least 24 to 30 inches of space around each side of the bed for optimal comfort and accessibility. This extra clearance ensures you’re not bumping into furniture or walls during daily use.

Use this room-size chart in tandem with the mattress size guide above to visualize the right fit for your home—whether you’re furnishing a master bedroom, guest room, or apartment studio.

Antique Beds and Irregular Mattress Sizes

If your home is filled with antiques and vintage finds, you may want an antique bed to fit your decor. The next challenge is to source an appropriate mattress.

Many antique beds were about three-quarters of the width of today’s full sized mattress. These smaller beds are often called three-quarter beds for this reason today. They are about 48 inches wide compared to 54 inches for today’s double mattress.

Many vintage beds are the same length as today’s full mattress at 75 inches. That said, variations based on time period and maker are common. Older antique beds might be much shorter.

Other irregular bed sizes include a Texas or athletic king (70 by 82 inches), California queen waterbed (60 by 84 inches), and California king waterbed (72 by 84 inches).

Thankfully, there are many mattress companies that specialize in custom orders for irregular or antique beds. Measure the interior dimensions of the bed frame you’ll use, then call mattress companies for their quotes.

You can also convert your vintage bed to work with a full mattress, but only attempt this if you are handy and have some time and guidance.

Aside from antique beds, there are irregular mattress sizes, like RV mattress sizes that are shorter and more compact to place less stress on a camper.

When dealing with antique or custom frames, it’s important to double-check interior frame dimensions—many older beds don’t follow modern standards, and misjudging by even an inch can lead to poor mattress fit or slippage.

Non-Standard Mattress Sizes Explained 

In addition to standard mattress sizes, there are several non-traditional dimensions designed for unique setups or taller sleepers. Here’s a breakdown:

• Short Queen (60″ x 75″) – Often used in RVs and campers where length must be sacrificed to fit compact frames.
• Olympic Queen (66″ x 80″) – Wider than a standard queen, ideal for couples who want more space but can’t accommodate a king.
• Wyoming King (84″ x 84″) – A true square bed, offering luxury-level width and length—popular for co-sleeping families.
• Texas King (80″ x 98″) – A long, wide bed perfect for taller individuals who also want expansive width.
• Alaskan King (108″ x 108″) – The largest oversized mattress available, designed for huge master suites and co-sleeping with multiple children or pets.

These specialty mattress sizes aren’t typically available in standard retail stores but can be custom-ordered from select manufacturers. If you’re considering one, be sure to verify your room dimensions carefully before purchase.

Custom-size mattresses are commonly used for boats, RVs, trailers, and even built-in bed platforms where space constraints require precision sizing.

These irregular options aren’t always listed in traditional mattress size charts, so if you’re building a full reference or mattress dimensions guide, it’s worth noting that some brands offer “short queen,” “Olympic queen,” or “Wyoming king” sizes by request.

How to Choose a Mattress Size

There are several factors to determining the best bed size for you. Questions to ask yourself include how much room space a bed can take up and where the room is located, how many people will use the bed, and how much you can budget on a mattress.

How Big is the Room?

The first consideration is practical — your room size. You’ll need to make sure your bed will actually fit in the space. Measure the width of each wall, and consider the other furniture you’ll need to accommodate. If you are happy with a long and short side of the bed against the walls, you can fit a larger mattress.

Many people prefer to have space on either side of the bed, as it’s generally considered more aesthetically appealing. Measure any nightstands you plan to place there, and leave enough space to fit them comfortably on either side of the bed. Don’t forget your door will take up space as it swings open.

When planning for a mattress, also factor in ceiling slopes, baseboards, or any architectural quirks that could restrict usable space—especially in attic rooms or converted lofts.

Where is the Bedroom?

This is not the most important consideration when shopping for mattresses, but it’s still worth considering. If your room is on the second floor or higher, you’ll have to think about how you’ll transport a larger mattress up to your bedroom. Choosing a king mattress in a box can make it easier to carry up a flight of stairs.

Mattress-in-a-box options are available in all standard mattress sizes and are particularly convenient for apartment living or homes with narrow staircases.

How Many Sleepers?

Once you’ve determined what will fit into your room, think about your lifestyle. Single sleepers might be happy with a double bed or even a twin. If multiple children sleep in one room, consider mattresses for bunk beds.

For those who share a mattress, you’ll likely want a queen size bed. If you have space for a larger mattress for couples in a master bedroom, you might sleep more comfortably in a king bed. Think about how luxurious it is to spend the night in a roomy hotel bed.

If you’re tall, you might want the extra length and legroom of a California king size. The California King is still wide enough to accommodate two sleepers, though it is narrower than a traditional king.

Couples who sleep with a child or pet often benefit from a king or California king, where there’s enough surface area to avoid crowding. These options also reduce sleep disturbances caused by movement.

Read Also: What is the Difference Between a Texas King and a California King?

How Much To Spend?

The last aspect to consider is your budget. Naturally, larger mattresses cost more. A king size mattress is more expensive than a queen or a double, and a California king is even pricier. Twin or twin XL sizes are common choices when shopping budget mattresses.

You might want to spend more on your main sleeping space, since you will be using it every night and comfort is top priority. You can save on mattress in your guest room or similarly with a smaller mattress.

The type of mattress you’re interested in will also affect your budget. For example, hybrid and latex mattresses generally cost more than memory foam and traditional innerspring mattresses. So it may worth considering what else your ideal mattress has as you put together a budget.

When comparing mattress dimensions, factor in accessory costs as well—larger beds require bigger sheets, duvets, and bed frames, which can significantly add to the overall budget.

Saving Money on All Mattress Sizes

Understanding when and where to do your mattress shopping can help you save significantly on the most comfortable mattress for your needs.

Know the Best Places to Shop

There are so many shops where you can buy a mattress, from mattress showrooms to furniture stores and even select department stores. What is the best place to buy a mattress, then?

A significant way to save money on any size is by looking at online mattresses. Not only is it more convenient to browse mattress options online, but the prices are often lower than what you would find in a more traditional mattress store.

Online mattresses are also typically mail order mattresses, so the bed will ship straight to your front door. In other words, you don’t have to leave your house to choose or pick up a mattress.

Some online brands even offer size-specific discounts, especially on less commonly purchased options like full XL or California queen mattresses. Signing up for email alerts or browsing clearance sections can lead to additional savings.

Many top mattress retailers now offer sleep trials of 100 nights or more—even for specialty mattress sizes—which lets you test the fit and comfort in your own space without risk.

SEE ALSO: The Best Place to Buy a Mattress & 7 In-Store Myths

Know the Best Times To Shop

Another way to save money is by shopping for mattresses when they go on sale. The main mattress sales throughout the year are:

• Presidents Day Mattress Sales
• Memorial Day Mattress Sales
• 4th of July Mattress Sales
• Labor Day Mattress Sales
• Columbus Day Mattress Sales
• Black Friday Mattress Sales
• Cyber Monday Mattress Sales

By taking advantage of the best times to buy a mattress, you can snag even a luxurious king or Cal king mattress at an affordable price.

Keep in mind that some retailers also host size-specific flash sales—for example, discounts on queen mattresses in the spring or twin XLs during back-to-school season.

Many brands also offer bundled deals during sale periods, where you can get free pillows or a bed frame with purchase—this adds extra value to any mattress size you’re shopping for.

FAQs

What is the best bed size for couples?

The best bed size for couples depends on what you need out of your bed. If you need a smaller, more affordable bed that you can both enjoy, a queen might be for you. If you need a long bed to accommodate an extra-tall partner, you may need a California king.

Those who need the standard amount of sleeping space for adults probably need a regular king. The standard king is also the size you need to plan for if you want to do a split king using two twin XL mattresses.

Which mattress sizes make a split king?

Two twin XL mattresses in the same standard king size mattress frame make a split king. Split kings are fantastic for a number of reasons. These beds allow couples to choose their firmness level and mattress material while still sleeping in the same bed. Split kings also allow you to use different adjustable base settings.

How big of a room do I need for a king size bed?

King size beds are almost a perfect square. They’re over 6 feet wide and more than 6 feet long. That means you need a room that’s at least 10 feet wide and 9 feet long. However, a king size bed will be stuffed pretty tight in a room that size, even though it will technically fit. Kings are better off in a 12 by 12-foot room to give you plenty of clearance and space for furniture.

Can I use box springs under a California king bed?

You can use box springs under any size bed as long as it’s an innerspring mattress. Box springs were designed for lighter-weight innerspring beds. So you can use a box spring set that corresponds to the size of your innerspring mattress, whatever size it is.

However, box springs will not work with any other mattress type, regardless of size. All-foam and hybrid mattresses are just too heavy for box springs. They’ll overcompress and break them.

What is the best bed size for tall sleepers?

That depends. If you’re 6 feet tall or just over, you should be able to sleep on any bed that’s 80+ inches long. That means twin XLs, queens, and kings will all work just fine.

If you’re several inches over 6 feet tall, you may have to get a California king. These 84-inch beds might be the only ones long enough to accommodate you.

What is the difference between a full and a full XL mattress?

The full and full XL mattresses have the same width—54 inches—but differ in length. A full XL mattress measures 80 inches long, while a standard full is only 75 inches. That extra 5 inches makes a significant difference for taller individuals who want more legroom without upgrading to a queen.

When comparing mattress sizes and dimensions, the full XL is an ideal choice for solo sleepers over 6 feet tall, especially in narrow bedrooms where width is limited. However, full XL beds are less common than other sizes, so you may need to search a bit more for bed frames or bedding.

Can two adults sleep on a full size bed?

Technically, yes—but it’s not ideal for long-term comfort. A full size mattress is 54 inches wide, which gives each adult only 27 inches of sleeping space—about the same width as a crib mattress.

While it may work temporarily for couples or in guest bedrooms, the full bed is best suited for single adults, teenagers, or older children. If you’re using a mattress size and dimensions guide to choose a bed for two people, a queen or king will offer significantly more space and better sleep quality.

Is a California king bigger than a standard king?

Not in total surface area, but yes in length. A California king mattress measures 72 inches wide by 84 inches long, making it 4 inches longer but 4 inches narrower than a standard king (which is 76 by 80 inches).

The California king is best for taller sleepers—especially those over 6’4″—while the standard king offers more width and is ideal for couples who value personal space. When evaluating mattress dimensions, think about whether you need more width (for pets or children) or length (for legroom).

What mattress size is best for a small room?

The best mattress size for small rooms is typically a twin (38 x 75 inches) or twin XL (38 x 80 inches). These compact sizes are perfect for dorms, guest rooms, and studio apartments where floor space is limited.

If you’re furnishing a small room but want a little more space to spread out, a full size mattress can also work—especially for single adults. Just be sure to leave at least 24–30 inches of clearance around the bed for ease of movement, as many mattress size guides recommend.

What size mattress do most people buy?

The queen size mattress (60 x 80 inches) is the most popular mattress size in the U.S. It strikes a balance between comfort, affordability, and room compatibility—making it suitable for both couples and solo sleepers.

According to most mattress size and dimension guides, the queen fits comfortably in bedrooms that are at least 10 by 10 feet, and it’s often the go-to choice for master bedrooms in apartments or smaller homes. If you want enough room to stretch out without overwhelming your space—or your budget—the queen is usually the best all-around option.

Rest Easy With a New Mattress

Knowing popular mattress sizes can put standard dimensions into context. Once you have an idea of what your sleeping space can accommodate, think about the best mattress for your lifestyle.

A single person may want to save money and choose a smaller bed. Meanwhile, those sharing a mattress might prefer the extra space afforded by a queen or king. Tall people may need an extra-long bed.

Consider your lifestyle and budget before researching mattresses on the market. Sweet dreams and feel free to refer back to this mattress size guide as needed.