Log in
If you're currently using a single bed but find it a bit cramped and are considering upgrading to a semi-double for more space, this article explains the basics of semi-double beds, how to choose one, and how it will fit in your room.
If you want to achieve more comfortable sleep while maintaining room space, please refer to this article.
What is a semi-double size?
The standard size for a semi-double bed is 120 cm wide x 195 cm long. However, the exact size may vary slightly depending on the bed manufacturer, so be sure to confirm the dimensions before purchasing.
A semi-double bed is larger than a single bed but smaller than a double bed. Despite the name "semi-double bed," you might imagine it's for two people. However, in reality, most people find it too small for two.
How many tatami mats is that?
Although it varies by region, the standard size of one tatami mat is generally 182 cm x 91 cm, so a semi-double bed is approximately 1.5 tatami mats.
What size room is recommended for a semi-double bed?
For a bedroom, a 4.5-tatami room still leaves ample space, allowing you to place a side table or open and close storage furniture without issue. If a clear path from the door to the bed can be secured, it can be installed, but it might make the room appear smaller. Therefore, placing it in a room of 6 tatami mats or larger is recommended if possible.
Also, if you live in a 1K or studio apartment, it's safer to assume that placing a semi-double bed in a room smaller than 5 tatami mats will be difficult.
Depending on the room's layout, the doors or drawers of other furniture might not open, or electrical outlets might become inconvenient to use, so be sure to check the bed's placement beforehand.
Additionally, when purchasing a large bed, check if the delivery route—including common areas of the apartment building, elevators, entrance and room doors, and hallways—is clear. The product's detail page will indicate the width and space required for delivery.
Who is a semi-double bed suitable for?
A semi-double bed is suitable for those who want to sleep spaciously alone, or for those who want to co-sleep with a small child (infant to toddler). It is especially recommended for those who find a single bed slightly too narrow.
Furthermore, a wide semi-double bed can also be used as a sofa, making it suitable for single residents. If you have 7 to 8 tatami mats or more, there will be ample space even when placed in a 1K or studio apartment.
Who is a semi-double bed not suitable for?
While it is possible to place it in a 1K or studio apartment smaller than 6 tatami mats, it might be better to choose a single size as the bed would occupy most of the room's space, creating a sense of pressure.
Also, while a semi-double bed is wider than a single bed, it is not spacious enough for two adults.
The bed needs to be large enough to turn over in
The average shoulder width for Japanese people is said to be about 44 cm for men and 39 cm for women. If sleeping with arms slightly outstretched, it's about 60 cm for men and 55 cm for women.
To turn over smoothly, you also need an additional 20 cm of space on each side. This means men need about 100 cm (60 + 20 + 20 cm) and women need about 95 cm (55 + 20 + 20 cm).
A semi-double bed is generally 120 cm wide, which means there's no space for two adults to turn over; it's barely enough to sleep on your back. While it can accommodate two people temporarily, such as for guests, it makes turning over difficult and can reduce sleep quality, so it's not recommended for regular use by two people.
You'll sleep more comfortably with two single-sized beds.
If you can't accommodate a larger bed, two single-sized mattresses, such as those that can be folded and stored during the day, will provide more comfortable sleep for two people.
Comparison with single size
Let's compare it with the standard single size bed.
Single Size
The standard size is 100 cm wide x 195 cm long.
Single beds are the most common size, so there is a wide variety of mattresses and covers available. They are fine for smaller individuals or those who don't toss and turn much, but taller individuals or those who move a lot may find them a bit cramped.
Semi-Double Size
The standard size is 120 cm wide x 195 cm long.
For those currently using a standard single bed, it might be easier to imagine it as being about 20 cm wider. The slightly increased width provides more room, making it recommended for those who find single beds a bit narrow or who want to sleep more spaciously.
Key points for choosing a semi-double bed
Here are three key points to consider when choosing a comfortable semi-double bed.
1: Room Size
If you are currently using a single bed, choose a semi-double bed after considering the size of the room where you will place it.
If there is ample space, there's no problem. However, if the room is not spacious enough, it may create a feeling of oppression or make other furniture difficult to use, so be careful.
If you are concerned about room size, a sofa bed, a foldable bed, or a loft bed is recommended.
2: Bed frame material
The atmosphere of your room can change significantly depending on the bed frame material, so choose one that suits your preferences.
Wood Frame
A bed frame made of wood. Colors range from pale shades to beige and dark tones. The wood grain design creates a natural and gentle ambiance.
Steel Frame
Steel frames, made of steel pipes, are also known as pipe beds or iron beds. Many products are affordable and very light, making them easy to transport and assemble.
Synthetic Leather Frame
Genuine leather is rarely used for beds because it is vulnerable to water; most products are fabric processed with synthetic resin to mimic leather. They have elasticity and a glossy finish, creating a sophisticated look.
Fabric Frame
A frame made of synthetic fiber fabric. Its soft touch makes it safe for homes with small children.
3: Functionality
Choosing functions that match the size of your bedroom and your lifestyle can enhance comfort.
With a sofa bed or a foldable bed, you can use it as a sofa when not sleeping or fold it to make the room more spacious. A loft bed allows you to utilize the space underneath, and a bed with storage can help declutter your room and save space that would otherwise be used for storage furniture.
Semi-double bedding size
If you're buying a semi-double bed, you should also get a semi-double duvet. Here are the common sizes for fitted sheets and duvets.
Semi-double fitted sheet size
The standard size for a semi-double fitted sheet is 120 cm wide x 210 cm long. It is 20 cm wider than a single size.
Semi-double duvet size
The standard size for a semi-double duvet is 170 cm wide x 210 cm long. It is 20 cm wider than a single size.
Comparing fitted sheets and duvets, their lengths are the same, but the duvet is 50 cm wider. Therefore, when purchasing covers, be sure to check not only "single" or "semi-double" but also whether they are for a fitted sheet or a duvet.
Choose a size for sound sleep
Upgrading from a single bed to a semi-double bed is meaningless if the mattress doesn't suit you. To achieve quality sleep, choose a product with the right firmness and comfort that perfectly fits your body.
