What Is the Biggest Bed Size?

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Ask anyone what the biggest bed size is, and you will surely get different answers. Some would say it is either the Queen or King. Others would nominate the California King. And there would be those who would have no idea which one to pick. Do not worry, as the diversity of people’s responses is normal and expected. So, until the presence of a universal system that sets standards for bed sizes globally, there is no single correct reply to this question.

The King or Eastern King bed is the largest bed size in terms of width and sleeping area, and the California King bed when it comes to length. But outside of standard mattress sizes, nothing beats the square-shaped Alaskan King, measuring at 274 by 274 centimeters.

To say that people are mistaken when they think California Kings are bigger than standard King beds would be incorrect. If you find this statement confusing, stick around and let this guide enlighten you on the biggest bed size, why it differs from place to place, and what room space can fit the bed size you have always wanted.

Big Bed with White and Blue Linen

What Bed Size Is the Biggest? 

Determining the biggest bed size can be subjective. There is no single answer. I say this because the naming standards on different bed sizes and their respective measurements vary across the globe. Availability is a factor, too. In countries where only four or five mattress standards exist, the King is likely the biggest size bed. If you associate the bed size with a specific aspect – say, length – then the California King bed will be the largest standard bed size. But if you take the sleeping area into account, then the Alaskan King dominates all other bed sizes.

To address its subjectivity, I have put together the biggest bed size available per country or region. Note that this information does not encompass all countries, as each has its own measurement system. Others simply follow international standards set by IPSA and other recognized organizations.


Traditionally, Europe has more variations in bed size standards than anywhere else in the world. Examples of these variations are 80- or 140-cm-wide bed sizes like the Piazza e Mezza Francese (meaning “French 1 ½ places”) in Italy and Casal (meaning “double”) in Portugal, which you will not find in other places. And while a single set of standards does not exist yet, a few sizes have become more commonly accepted and adopted in recent years. Out of these standard sizes, the Super King is the biggest king size bed in the region. It measures 183 by 200 centimeters.

North America

In the United States, width determines what the biggest bed size is. This makes the King or Eastern King bed the biggest size you can get based on US standard manufacturing. It measures 193 by 203 centimeters. If you go for length, the California King is your best bet. It is longer and narrower than a standard King and measures 183 by 213 centimeters. If you are willing to go beyond standard sizes, the Alaskan King is the ultimate bed size choice, measuring at 274 by 274 centimeters. This bed’s size is guaranteed to give you more than sufficient sleeping space and is good for sharing with 2-3 other family members.

Other countries in this region, like Canada, follow the same principle. However, the Super King is its biggest bed size available. It measures 217 by 215 centimeters and is somewhat larger than a US Wyoming King or Emperor bed, already falling under the oversized-mattress category.


Countries in Oceania and the Pacific predominantly follow international-standard mattress sizes but tend to name them differently. In Australia, for instance, the largest bed size is the Super King that measures 204 by 204 centimeters. It is closest to the overall dimensions of a US Eastern King but slightly wider and square-shaped. What is the biggest size bed in New Zealand? Kiwis refer to it as the California King – despite the bed size being shorter than the US version, measuring at 203 by 203 centimeters.


South Africa’s largest bed size, the Super King, is quite similar to that of New Zealand and Australia, only falling short by 3-4 centimeters in both length and width. It is 200 by 200 centimeters and is available with those specific measurements only. All other smaller bed sizes in the country are available in either 188- or 200-centimeter lengths referred to as standard and XL variants.


The majority of Asian nations follow international standards for bed sizes. However, the same cannot be said for all. Take the example of China, which has three bed-size categories. Its largest bed is 180 cm by 200 centimeters and is almost similar to a Super King bed in Europe and a Queen bed in Taiwan. India only has four standard beds, of which the King Bed is the largest (183 by 198 centimeters). Indonesia’s largest bed size perfectly matches South Africa’s Super King in name and measurement.

Japan has the most extensive bed sizes out of all the countries in Asia (followed by Singapore), while Taiwan has the most generous bed sizes. The biggest bed size in Japan is called King Long and measures 194 by 205 centimeters. In Singapore, it is the standard US King. In Taiwan, it is the King bed, which roughly has the same length and width as a US California King.

What Determines Bed Size

Large Bed with White Pillows and Sheets

Although the United States, Europe, and Japan have their respective systems that set standard mattress sizes, it is not the same everywhere else. Some countries and manufacturers only refer to four or five bed sizes, while others have at least seven or eight. This is not taking into account custom sizes made available to consumers by companies. For one, IKEA only goes by four standard sizes with the beds, mattresses, and beddings that it offers.

Whether standard or oversized, bed sizes are based on the mattress’s size and the degree of embellishment of the bed frame, which differs from country to country. A perfect example is Taiwan – its Double bed matches the width of a US Queen bed. Another good example is Japan. Although most of its bed sizes are almost similar to IPSA standards, you will notice that all of them are 195 centimeters long compared to the usual 190-, 200-, or 203-centimeter length in all other parts of the world.

Manufacturing tolerances, amount of padding, support type, and technology likewise impact how a bed size is determined. Sleep Number and split-type mattresses tend to require slightly bigger beds versus a regular, permanent-use one. A Texas King, one of the biggest mattress sizes in the market, will naturally need a much bigger bed than standard ones. The thickness of a mattress will have little to no effect on the bed size. If two mattresses in comparison are nominally the same in length and width, they would fit a same-sized bed frame or spring box regardless of their depth.

Which Bed Size for Your Room

If only for curiosity, then King-size beds are the biggest bed sizes available in the market. But if you want to find out the biggest mattress size that will fit in your sleeping chamber, you need to know how much room space you have and who will use the room. As a general rule, you need to have at least 30 inches or three feet of space all around your bed for movement. Note that this calculation doesn’t include any other pieces of furniture inside your bedroom. Hence, a multi-functional space would need an extra allowance of 15-20 inches to fit a particular bed type.

  • Standard King or Eastern King – This bed will fit reasonably well in either a 10′ x 12′ or 11′ x 13′ bedroom. However, a 13′ x 13′ or larger room is recommended to sufficiently accommodate some furniture and accessories, and if you want an open, spacious feel.
  • California King – A 10′ x 12′, 11′ x 13′, or 13′ x 19′ bedroom can hold this bed type. The latter dimensions are preferred if you have furniture pieces. These suggestions are the bare minimum- hence, a larger room would work much better. Just keep in mind that a California King bed would need a space with more length than width compared to a standard King.
  • Alaskan King – The smallest room this bed type can fit into measures 12′ x 12′. Your room does not necessarily have to be square-shaped like this bed, but any side of it cannot go below 12 feet.

In this video by Mattress Clarity, the presenter shows how each standard bed size will fit in an average bedroom (time stamp at 5:05) and throws in a few pointers on how to choose the best bed size.

These recommended room spaces can only hold standalone beds. If your frame has a trundle bed or a pullout, you may need to double the length of your guest room or bed-chamber to accommodate additional sleepers.

Measuring Your Mattress

Before we start this section, watch this video by US-Mattress.com that talks about the six standard mattress sizes and their corresponding measurements. The presenter even provides useful tips on how to measure your mattress without a measuring tape. He does quite a good job in making the presentation educational but light through his funny antics.

For reference, here is a list of different mattress sizes. These should help you understand the slight variations between any two kinds and give you a good idea of how huge a bed you will need to fit it in. The table below comes with metric and imperial measurements and is divided into four different sections (unmarked measurements are ISPA-standard):

International Standard Mattress Sizes

Bed Type Metric Imperial
Single (S) or Twin (T) 96.5 x 190 cm

90 x 190 cm (UK/AUS)
90 x 200 cm (Euro)
91 x 188 cm (TWN)
97 x 195 cm (JAP)
99 x 188 cm (SG)
106 x 188 cm (TWN)
3’2″ x 6’3″

3’0″ x 6’3″ (UK/AUS)
3’0” x 6’7” (Euro)
3’0″ x 6’2″ (TWN)
3’2″ x 6’5″ (JAP)
3’3″ x 6’2″ (SG)
3’6 x 6’2″ (TWN)
Single Long (SL) or Twin XL (TXL) 96.5 x 203 cm

92 x 203 cm (AUS)
99 x 203 cm (SG)
3’2″ x 6’8″

3’0″ x 6’8″ (AUS)
3’3″ x 6’8″ (SG)
Double (D) or Full (F) 135 x 190 cm

138 x 188 cm (SG/AUS)
140 x 195 cm (JAP)
140 x 200 cm (Euro)
4’6″ x 6’3″

4’6″ x 6’2″ (SG/AUS)
4’7″ x 6’5″ (JAP)
4’7” x 6’7” (Euro)
Double XL (DXL) or Full XL (FXL) 135 x 203 cm 4’6″ x 6’8″
Queen (Q)

**Queen beds are called King in the UK and Double in Taiwan
152 x 203 cm

152 x 190 cm (SG)
152 x 200 cm (UK)
150 x 203 cm (NZ)
160 x 195 cm (JAP)
160 x 200 cm (Euro)
152 x 188 cm (TWN)
5’0″ x 6’8″

5’0″ x 6’3″ (SG)
5’0″ x 6’7″ (UK)
5’0″ x 6’8″ (NZ)
5’3″ x 6’5″ (JAP)
5’3” x 6’7” (Euro)
5’0″ x 6’2″ (TWN)
King (K) or Eastern King

**Referred to as Super King in New Zealand, South Africa, Indonesia, and Europe
, and Queen in Taiwan
193 x 203 cm

183 x 200 cm (UK/Euro)
183 x 203 cm (AUS/NZ)
194 x 195 cm (JAP)
200 x 200 cm (SA/IND)
182 x 188 cm (TWN)
6’4″ x 6’8″

6’0″ x 6’7″ (UK/Euro)
6’0″ x 6’8″ (AUS/NZ)
6’4″ x 6’5″ (JAP)
6’7″ x 6’7″ (SA/IND)
6’0″ x 6’2″ (TWN)
California King (CK)

**Called a King bed in Taiwan and a Super King in Australia
183 x 213 cm

182 x 212 cm (TWN)
203 x 203 cm (NZ)
204 x 204 cm (AUS)
6’0″ x 7’0″

6’0″ x 7’0″ (TWN)
6’8″ x 6’8″ (NZ/AUS)

Oversized Mattress Sizes

Bed Type Metric Imperial
Texas King, Grand King, or Athletic King 203 x 249 cm 6’8″ x 8’2″
Wyoming King or Emperor

**Called a Super King in Canada
213 x 213 cm
217 x 215 cm (CAN)
7’0″ x 7’0″
7’1″ x 7’0″ (CAN)
Super Emperor 229 x 213 cm 7’6″ x 7’0″
Caesar 244 x 213 cm 8’0″ x 7’0″
Alberta King or
Alaskan Queen
244 x 244 cm 8’0″ x 8’0″
Super Caesar 274 x 213 cm 9’0″ x 7’0″
Alaskan King 274 x 274 cm 9’0″ x 9’0″

Standard Mattress Sizes in Other Countries

Bed Type Metric Imperial
Cot 60 x 120 cm (UK) 1’11” x 3’11” (UK)
Crib 70 x 132 cm 2’3″ x 4’4″
Toddler or Junior 70 x 140 cm (UK)
70 x 160 cm
2’3″ x 4’6″ (UK)
2’3″ x 5’3″
Small Single 75 x 190 cm (UK) 2’6″ x 6’3″ (UK)
Wide Single

**Referred to as Three-Quarter in South Africa and Super Single in Singapore
107 x 190 cm (SG/UK)
107 x 188 cm (SA)
3’6″ x 6’3″ (SG/UK)
3’6″ x 6’2″ (SA)
King Single 107 x 203 cm (SG) 3’6″ x 6’8″ (SG)
Small Double 122 x 190 cm (UK)
120 x 200 cm (Euro)
4’0″ x 6’3″ (UK)
4’0” x 6’7” (Euro)
Semi-Double 122 x 195 cm (JAP) 4’0″ x 6’5″ (JAP)
Olympic Queen, Super Queen, or Expanded Queen

**New Zealand’s King bed matches these dimensions
168 x 203 cm 5’6″ x 6’8″
Hotel King 183 x 203 cm 6’0″ x 6’8″
King Long 182 x 198 cm (SG)
194 x 205 cm (JAP)
6’0″ x 6’6″ (SG)
6’4″ x 6’9″ (JAP)

Less Common Mattress Sizes

Antique Single 91 x 183 cm 3’0″ x 6’0″
Twin XXL 95 x 212 cm 3’1″ x 7’0″
Single Waterbed 91 x 208 cm 3’0″ x 6’10”
Super Single Waterbed 119 x 208 cm 4’0″ x 6’10”
Antique Double or Three-Quarter 122 x 183 cm 4’0″ x 6’0″
Queen Waterbed 147 x 208 cm 4’10” x 6’10”
Short Queen or
RV Queen

**Matches the size of a Wide Double in Japan
152 x 191 cm
152 x 195 cm (JAP)
5’0″ x 6’3″
5’0″ x 6’5″ (JAP)
King Waterbed 178 x 208 cm 5’10” x 6’10”
Short King or
RV King
183 x 191 cm 6’0″ x 6’3″

Using this guide as a basis, measure your mattress properly. Start from where it rests on the spring box to the top of the mattress, including any pillow top. Factor in the measurement of your spring box for encasements. Make sure to remove any beddings before measuring to get the exact size of your mattress and bed.

When choosing a new bed frame, add 2-5 inches to each side of your mattress dimensions. This extra space is intended for the bed frame’s structure and any special features like drawers, shelves, or upholstery that it might come with.

If you currently happen to own a less-common bed size, I recommend switching to a market-standard one. Doing this will give you more options and help you save up on expenses by avoiding costly custom-made beds.

Large Bed with Gray Comforter

Conclusion – What Is the Biggest Bed Size?

Depending on your location, room space, and budget, you may consider the Eastern or standard King, the California King, or the Alaskan King to be the largest bed size. Based on US manufacturing standards, the Eastern King dominates in width while the California King in length. However, the Alaskan King bests these bed sizes in both aspects. So, take out that retractable measuring tape and determine what’s the biggest bed size that’s right for you.

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