The A-to-Z Mattress Sizes & Bed Dimensions Guide

Today you’re going to learn precisely how to choose the right sized mattress for your needs.

What you’re going to find is all the tips, comparisons, and answers to common questions that thousands of mattress shoppers use to successfully choose the right mattress size every day packed into the ultimate one-stop guide.

If you’re in the market for a new mattress but are unsure exactly which size is going to be the right buy for you, then you’ll love the size guides, comparisons, and actionable information contained in this guide.

Let’s get you started on your way to the best nights’ sleep you’ve ever had.

Mattress Size Comparison Table

Mattress SizeDimensions (in)Dimensions (cm)Good Choice For
Crib Mattress27.5 x 5270 x 132Babies
Toddler Mattress27.5 x 5270 x 132Toddlers who have moved from the crib
Junior Mattress27.5 x 6370 x 160Children
Twin/Single Mattress38.5 x 74.598 x 189Single adult
Twin XL Mattress38.5 x 79.598 x 202Single adult
Full/Double Mattress53.5 x 74.5136 x 189Single adult or couples
Queen Mattress60 x 79.5152 x 202Couples
King Mattress76 x 79.5193 x 202Couples with children/pets, larger couples
California King Mattress72 x 83.5183 x 212Couples with children/pets, larger couples

illustration of a king bed

Standard Mattress Sizes

Crib Mattress Dimensions

  • Dimensions: 27.5 inches wide by 52 inches long (70cm x 132cm)
  • Recommended For: Babies.
  • Not Recommended For: Anyone larger than a toddler.
  • Minimum Room Size: 87” x 82”

The Crib mattress is the smallest standard sized bed and designed for exclusive use by babies who sleep in an enclosed crib.

Crib mattresses are firmer than a standard adult mattress as softer beds can be potentially dangerous for a baby’s breathing since they can cause suffocation, and a firmer mattress provides more support for growing bones.

Crib mattresses are designed to fit a standard crib, around 28 x 52 inches. There should be no more than a 1½ inch (4cm) gap between the side or end of the crib when the mattress is pushed all the way into a corner.

This translates to roughly two fingers. Any gap larger than this means the fit is incorrect; bigger gaps are a potential suffocation hazard.

Crib mattresses are often made from light materials that allow for portability and ease of cleaning.

Toddler Mattress Dimensions

  • Dimensions: 27.5 inches wide by 52 inches long (70cm x 132cm)
  • Recommended For: Toddlers who have outgrown the crib and are graduating to their first bed.
  • Not Recommended For: Babies. Toddler mattresses are generally softer than crib mattresses and present a suffocation hazard for infants.
  • Minimum Room Size: 87” x 82”

As the name suggests, Toddler mattresses are designed to be a first bed once a child has outgrown the crib. They are the exact same size as a Crib mattress and act as an intermediary between the crib and a Junior or Single bed.

The differences between a Crib mattress and a Toddler mattress lie more in how they’re used more than anything else.

Obviously, a toddler bed is not enclosed like a crib (although they may have side rails), and a toddler bed can make use of pillows, a comforter, and a top sheet, none of which are used in a crib.

Generally, Toddler mattresses will be softer than Crib mattresses as there is not the same suffocation danger. At this stage, beds can begin to be tailored more toward comfort than practicality.

Because Crib and Toddler mattresses are the same size, double-sided mattresses that cater to infants and toddlers are often a popular choice for parents who don’t want to buy two beds that will soon be grown out of.

Junior Mattress Dimensions

  • Dimensions: 27.5 inches wide by 63 inches long. (70 x 160cm)
  • Recommended For: Younger children.
  • Not Recommended For: Older children/teenagers.
  • Minimum Room Size: 99” x 105”

The Junior mattress is the same width and 11 inches (28cm) longer than Crib and Toddler mattresses.

The Junior mattress is not as widely popular as other standard sizes. Youth beds, like crib beds, generally have a shorter useful life due to being outgrown.

Still, the Junior acts as a good intermediary for children who may have outgrown a Toddler bed but don’t yet require the extra room that comes with an adult-sized bed.

They also act as a more economical option for parents who don’t wish to invest in a Toddler bed — the Junior is suitable for toddlers and should last them through most of their childhood.

Twin/Single Mattress Dimensions

  • Dimensions: 38.5 inches wide by 74.5 inches long. (98 x 189cm)
  • Recommended For: Children, small to average single adults. Rooms with not a lot of space.
  • Not Recommended For: Larger adults, people who like to spread out or toss and turn, couples.
  • Minimum Room Size: 99” x 105”

The standard Twin (Single) mattress is 11 inches (28cm) wider and 11.5 inches (29cm) longer than a Junior mattress.

The Twin mattress is the minimum size that would be suitable for most adults, providing the minimum amount of room for an adult to sleep comfortably. They are also a good option as a kids’ bed that would be suitable enough to last well into their teens.

Twin beds are perfect for small rooms where space is at a premium or where two or more beds are required, such as a guest bedroom or holiday home.

A twin is probably not well suited to larger adults, those who like to spread and stretch out in bed, or who toss and turn a lot.

Twin XL Mattress Dimensions

  • Dimensions: 38.5 inches wide by 79.5 long (98 x 202cm).
  • Recommended For: Children, tall single adults. Rooms with not a lot of space.
  • Not Recommended For: Larger adults, couples.
  • Minimum Room Size: 104” x 105”

The standard Twin XL mattress is 5 inches (13cm) longer than a standard Twin/Single bed.

Like the Twin, the Twin XL is suitable for a single adult, albeit ones who need a bit more length, so if you’re on the tall side, a Twin XL should suit you better than a standard Twin while still being able to fit into pretty much the same sized space.

Full/Double Mattress Dimensions

  • Dimensions: 53.5 inches wide by 74.5 inches long (136 x 189cm).
  • Recommended For: Single adults, small to average couples, couples who enjoy sleeping close.
  • Not Recommended For: Larger couples.
  • Minimum Room Size: 114” x 105”

The standard Full (Double) mattress is 15 inches (38cm) wider and 5 inches (13cm) shorter than a standard Twin XL.

A Full-size bed is perfect for a single adult who prefers a bit more room to spread out but doesn’t need the extra size of a Queen.

It is also the minimum size that would be suitable for a couple, though most couples would probably prefer a Queen unless they prefer close-quarters sleeping, are restricted by space, or both are on the smaller than average side.

Queen Mattress Dimensions

  • Dimensions: 60 inches wide by 79.5 inches long (152 x 202cm).
  • Recommended For: Most couples (most popular bed size).
  • Not Recommended For: Couples with children or multiple pets who share the bed.
  • Minimum Room Size: 120” x 110”

The standard Queen mattress measures 6.5 inches (16.5cm) wider and 5 inches (13cm) longer than a Full/Double mattress.

The Queen bed is pretty much the gold standard for adult couples, being big enough that most couples have enough space to sleep comfortably without being too large to fit into most spaces.

Its suitability for most average couples means it is the size of choice for between a third to a half of all American adults.

King Mattress Dimensions

  • Dimensions: 76 inches wide and 79.5 inches long (193 x 202cm).
  • Recommended For: Couples who enjoy their own sleeping space, easily disturbed partners, couples with children and pets who share the bed
  • Not Recommended For: Rooms with not a lot of space.
  • Minimum Room Size: 136” x 110”

The standard King mattress measures 16 inches (41cm) wider and the same length as a standard Queen bed.

The King size bed is where you really start seeing some personal space. For couples who consider themselves sleep connoisseurs and really appreciate having extra room to spread out without touching their partner, the King mattress will fit the bill for most.

A King size is a sensible option for couples with a child or two who like to share the bed, or perhaps a pet that likes to curl up and sleep with them, providing there is adequate space for this large bed.

California King Mattress Dimensions

  • Dimensions: 73 inches wide and 83.5 inches long (183 x 212cm)
  • Recommended For: Tall couples, couples who enjoy their own sleeping space, easily disturbed partners, couples with children and pets who share the bed
  • Not Recommended For: Rooms with not a lot of space.
  • Minimum Room Size: 132” x 114”

The standard California King mattress measures 3 inches (7.5cm) narrower and 4 inches (10cm) longer than a standard King bed.

It is the largest ‘standard’ sized mattress that is commonly available. While bigger sizes are available, most people would not go larger than this.

The California King is one bed with a real aura of luxury — and acts almost as a status symbol, given their origin in the 1960s when a Los Angles company began making oversize beds for celebrity mansions.

You don’t need to have a mansion to own one — but you do need a bit more space to work with than your average bed.

Even couples on the larger side of average will have room to spare on a California King. If you have space for one, the California King is the perfect option for couples who are easily disturbed by their sleeping partner, who like to really spread out, or who toss and turn a lot.

It’s the perfect family option, too — if you have multiple kids who like to share the bed, multiple pets, or perhaps just one large one, there should be plenty of room for all on the California King.

Less Common Mattress Sizes

Believe it or not, these standard mattress sizes are not where it ends — there is a multitude of other less common sizes, mainly at the larger end of the spectrum.

Although you probably won’t find these in your average mattress retail store, some of the less-common standard-shape mattresses are:

Olympic Queen Mattress Dimensions

For couples who need a bit of extra width but either don’t quite need the size of a King or are restricted by available space, the Olympic Queen bed, measuring 66 inches wide by 80 inches (168 x 203cm), gives an extra six inches of width for couples who like a little extra distance between them.

Wyoming King Mattress Dimensions

If you thought the California King is as big as it gets, think again. Measuring in at 84 x 84 inches (213 x 213cm), the Wyoming King is an excellent choice for couples with more than one child, multiple or large pets who like to share the bed — providing the bedroom is big enough to fit a bed this large!

Alaskan King Mattress Dimensions

Unless you’re going for a crazy custom bed, this is as likely as big as you’ll find. The King of the Kings, the Alaskan King, requires a lot of space, measuring in at 108 x 108 inches (274 x 274cm).

Some families with young children enjoy all sleeping together in one bed, and this is one size of mattress that caters well to family bonding — or couples with a couple of spoiled Saint Bernards!

How to Choose the Right Mattress Size

Now we come to the meat of the guide, where we take a look at the factors anyone thinking about buying a new bed needs to take into account when choosing.

The last thing you’re going to want to do is to overlook anything and end up buying a mattress that does not quite suit your needs. Let’s now take a look at things to take into account when choosing the size of your next bed.

What to Consider When Choosing a Bed Size

1Your Height

It is recommended that a bed should be at least 6 inches (15cm) longer than the height of the person sleeping on it. According to the CDC, the heights of average Americans are 69 inches (175cm) for men and 63.6 inches (162cm) for women.

This means any size from a Twin up should provide adequate length for the average adult.

A Twin XL is perfect for a taller single person looking for a smaller bed that isn’t too wide. Queen and King size mattresses are the same length, making them great for taller couples, while a California King will fit the bill best for couples who are significantly taller than average.

illustration representing body height

2Your Body Size

Body size will determine the width of bed needed. As you can see in the size comparison chart, there is a tradeoff between length and width in standard adult bed sizes.

For couples, a Full (Double) mattress may be the minimum needed for adequate comfort, while the King and California King will provide the most sleep real estate for couples on the larger side.

illustration representing body size

3Single Person vs. Couple

Obviously, the larger bed sizes are not just for couples — the amount of room people like on a mattress is all personal preference.

But, if you are restricted by the amount of space you have and have to trade sheer size for practicality, then anything from a Twin to a Full (Double) bed should be suitable for solo sleepers.

For couples, the Full (Double) would be the absolute minimum appropriate size but likely wouldn’t suit most average couples. Any size from a Queen upwards should provide adequate personal space.

illustration representing single person vs. a couple

4Room Size and Layout

Obviously, one of the top factors that will dictate the bed’s size is the size of the room it’s going in.

The size of the bed you can fit in a room is not just dictated by the four walls, but by the other furniture in the room, the location of doors, and fixtures like lights and electrical outlets.

The primary consideration is making sure there is enough ‘circulation space’ — that is, you are able to move clearly around the room without obstruction and have enough space around furniture such as chairs and dressers.

The layout of the room also matters. Odd-shaped rooms and rooms with unmoveable fixtures such as built-in furniture or wall-mounted lights can restrict the bed’s location options and the size that can comfortably fit.

The standard clearance around the sides and end of a bed range from 30 inches at a minimum to 36 inches for a more comfortable clearance. This handy bedroom size guide shows the minimum sized room required for comfortable clearance around all standard sized beds.

Bed TypeMinimum Room SizeIf against the wall
Crib87 inches x 82 inches57 inches x 82 inches
Twin/Single99 inches x 105 inches69 inches x 105 inches
Full/Double114 inches x 105 inches84 inches x 105 inches
Queen120 inches x 110 inches 
King136 inches x 110 inches 
California King132 inches x 114 inches 
illustration representing room size

5Kids and Pets

If you have young children and/or pets that like to share the bed with you, then it’s better to go bigger — after all, there’s no point buying a bed that’s the perfect size for just you or you and your partner if you have rugrats or furbabies taking up valuable mattress real estate.

illustration of a kid and a pet

6Partner Disturbance

One partner who is a light sleeper paired with a partner who moves around a lot in their sleep can be a recipe for lousy sleep and grumpy mornings.

If movement during the night is an issue, then along with buying a mattress that has good motion isolation properties, you’ll also want one that’s big enough that any stray limbs don’t intrude on your side of the bed. A King or California King is your best bet if partner disturbance is an issue.

illustration representing partner distrurbance from movements

7Differing Preferences

Sometimes couples can agree on a lot — but not the feel of the mattress that they share.

Mattress sizes from Queen upwards are available in ‘Split’ versions — meaning each side of the bed can have different levels of firmness and feel, and partner disturbance is cut out of the picture, too.

illustration representing different mattress preferences of a couple

Mattress Thickness

When thinking about the right size mattress for your needs, it pays to take into account its thickness as well as the overall area it takes up. It’s not the case that beds get thicker the larger you go, either. It’s common nowadays to find multiple thicknesses for each size of mattress.

Most standard mattresses are in the range of 9 to 16 inches in depth (23 to 41cm), and it is the construction of the mattress and materials used that will be the main determinants of the bed’s thickness. All-foam mattresses tend to be thinner than, say, a hybrid or spring mattress.

Why Mattress Thickness Is Important

When considering the thickness of your next mattress, it is the weight of you and your partner that you mainly need to take into account. As a basic rule, the heavier you are, the thicker your mattress should be.

Heavier people tend to sink deeper into the bed. If the mattress is not thick enough, this can result in a lack of support and comfort due to sinking the full depth of the softer comfort layers and coming into contact with the firmer support layers below. Heavier people generally require a firmer mattress for this reason.

The downside of needing a thicker mattress is likely to be price. Thicker mattresses require more material to make and generally have more layers, so are typically more expensive, especially if it utilizes advanced foam technology, steel springs, or extra reinforcement.

illustration representing FAQs

Bed Sizing FAQs

What size of bed will be the best fit for my room?

The room size will be the primary determinant of the size of bed that will provide the best fit. Other considerations are things like the shape of the room and the size and location of any furniture and fixtures.

A good rule of thumb is to ensure a clear space between 30-36 inches (76-91cm) of clear space around the bed’s sides and end.

What mattress size is best for couples?

The minimum mattress size for an adult couple is the Full (Double). Queen beds are the most popular choice for couples, and anything above a Queen (King, California King) will have room enough for most couples.

Can a Full (Double) size bed comfortably sleep a couple?

Yes, but it is dependant on the size and sleep preferences of the couple. For most adult couples, a Queen is the minimum comfortable size and is the most popular choice.

A Double bed will comfortably sleep a smaller than average couple, or couples who like to be close to or snuggle with their partner when sleeping.

What’s the difference between a Full-size bed and a Double bed?

There is no difference. Full and Double are different names for the same size of mattress—both measure 53.5 inches (136cm) wide by 74.5 inches (189cm) long.

What’s the difference between a Twin bed and a Single bed?

There is no difference between a Twin and a Single mattress — they’re just different names for the same size mattress, measuring 38.5 inches (98cm) wide by 74.5 inches (189cm) long.

What’s the largest mattress size?

The largest standard mattress size is the California King, which measures 73 inches (183cm) wide and 83.5 inches (212cm) long. Overall, the largest mattress size is the Alaskan King, which measures 108 inches (274cm) by 108 inches (274cm).

What’s the most popular mattress size?

By far, the most popular mattress size is the Queen (60 inches [152cm] wide by 79.5 inches [202cm] long). In 2017, the Queen accounted for 47% of all mattresses in the USA.

Can two Twin beds make a King size bed?

No. While two Twin-sized mattresses together are the same width as a King size, the Twin is 5 inches (13cm) shorter than the King. Two Twin XL mattresses together are the same size as a King.

Is a Split King mattress the same size as a King mattress?

A Split King is essentially two Twin XL mattresses combined to make a King size. The footprint of a Twin XL is half that of a King, meaning two together make a King size bed.

Do I need a box spring?

Not all mattresses require a boxspring. The main benefits of a box spring are they increase the height of a bed, making getting in and out easier, and provide a flat, stable platform, and they can reduce shock and add extra bounce.

In some cases, using a box spring is optional. Other times it is necessary, for instance, if your mattress’s warranty requires one, or it is necessary to use one due to the type of bed frame.