What are the different sizes of mattresses: Get the best fit
If you want to know what are the different sizes of mattresses, the answer depends on your height, whether you share a bed, and the actual dimensions of your bedroom floor. UK mattress sizes include the small single (75x190cm), single (90x190cm), small double (120x190cm), double (135x190cm), king size (150x200cm), and super king (180x200cm).
I remember moving into my first small flat and buying a double bed without measuring the room first. It was a total mess. I could barely open my wardrobe door because the mattress took up every spare centimetre of floor space. Choosing a new bed is about more than just comfort because the physical dimensions dictate how you move around your room every morning. If you are currently looking at your bedroom and wondering what are the different sizes of mattresses, I can help you figure out which one actually fits your lifestyle and your floor plan.
A Detailed Look at UK Mattress Dimensions
Most of us just think of beds as small, medium, or large. In the UK, we have very specific standards for mattress widths and lengths. I have found that even a few centimetres can make a massive difference in how well you sleep. A standard single is great for kids, but a tall adult will likely find their feet hanging off the edge of a double. This happens because double mattresses are actually shorter than king size models.
Small Single and Standard Single
The small single mattress measures 75cm by 190cm. I usually recommend these for very small children or narrow guest rooms. A standard single is 90cm wide, which gives a bit more breathing room. I use a standard single in my spare room, and it fits most adults reasonably well for a night or two. These sizes are perfect for bunk beds or tight spaces where every centimetre counts.
Small Double and Standard Double
The small double, often called a queen or a four foot bed, is 120cm wide. It is a lifesaver for teenagers or solo sleepers who want to spread out. The standard double is 135cm wide. While many couples use a double, I personally find it a bit cramped. You only get about 67cm of space each, which is less than a child gets in a single bed. If you or your partner move around a lot, you might wake each other up.
King and Super King Sizes
A king size mattress is 150cm wide and 200cm long. That extra 10cm in length is vital if you are over six feet tall. I noticed a huge improvement in my sleep quality when I switched to a king because my ankles were finally supported. The super king is the largest standard size at 180cm wide. It is basically two single mattresses pushed together. It feels incredibly spacious and is the best choice if your kids like to climb into bed with you on Sunday mornings.
Standard UK Mattress Size Comparison Table
This table shows the exact measurements for the most common options available in shops today. Use these numbers to measure your bed frame before you buy anything new.
| Mattress Size | Width (cm) | Length (cm) | Best For |
|---|---|---|---|
| Small Single | 75 cm | 190 cm | Toddlers and narrow rooms |
| Single | 90 cm | 190 cm | Children and solo adults |
| Small Double | 120 cm | 190 cm | Solo sleepers wanting space |
| Double | 135 cm | 190 cm | Couples with small rooms |
| King Size | 150 cm | 200 cm | Tall people and couples |
| Super King | 180 cm | 200 cm | Maximum luxury and families |
Mistakes I Made When Checking Mattress Sizes
I once bought a beautiful king size mattress only to realise my old bed frame was a standard double. It sounds silly, but it is a very common error. You must check the dimensions of your specific bed frame because some frames, like sleigh beds or upholstered styles, are much wider than the mattress itself. I also forgot to measure the staircase. Getting a super king mattress around a tight corner in an old house is a nightmare. Always check if your chosen size can actually get into the bedroom.
Another point to consider is your bedding. If you upgrade from a double to a king, you will need all new sheets, duvets, and protectors. Those costs can add up quickly. I felt a bit frustrated when I realised my favourite linen set wouldn’t fit my new bed. Make sure you account for the price of new bedding when you decide to go for a larger mattress size.
How to Choose Based on Your Room Size
You need at least 60cm of walking space around the sides and foot of the bed. I like to use masking tape to mark out the mattress dimensions on the floor before I buy. This helps me see if I can still open my drawers or walk to the bathroom without stubbing my toe. If your room is roughly 3 metres by 3 metres, a double mattress is usually the limit for a comfortable layout.
For those lucky enough to have a large master bedroom, a super king acts as a great centrepiece. It fills the space and looks more proportional. If you are tall, ignore the width for a second and look at the length. Standard doubles are only 190cm long. If you are 185cm tall, your head will be right at the top and your feet will be dangling off. A king size gives you that extra 10cm of length which is non-negotiable for tall sleepers.
Frequently Asked Questions (FAQs)
Are IKEA mattress sizes the same as UK sizes?
No, IKEA often uses European sizes which are slightly different. A standard UK king is 150cm wide, but a European king is 160cm wide. I have seen many people buy an IKEA frame and a UK mattress only to find a 10cm gap down the side. Always double check the exact centimetre measurements on the label rather than just relying on the name of the size.
Can two adults sleep comfortably on a small double?
It is possible, but it is very tight. I would only suggest this for a guest room where people are staying for a short time. For a permanent sleeping arrangement, two adults usually need at least a standard double to avoid feeling restricted. A small double is really designed for one person who wants plenty of room to stretch out.
Is a king size mattress always longer than a double?
Yes, in the UK, a king size mattress is 200cm long while a standard double is 190cm long. This 10cm difference is often the main reason people upgrade. It provides the necessary legroom for anyone over six feet tall. If you find your feet touching the footboard of your bed, the extra length of a king size will solve that problem.
What size mattress do I need for a studio apartment?
In a studio, space is your most valuable asset. A small double is often the best compromise. It offers more sleeping surface than a single but leaves enough floor space for a desk or a small sofa. If you live alone, a small double is a great way to keep your living area from feeling like one giant bedroom.
How do I measure my current bed frame?
Use a metal tape measure for accuracy. Measure the inside of the frame where the mattress sits, not the outside edges. Measure the width from the inside of the side rails and the length from the headboard to the footboard. This ensures you buy a mattress that fits snugly inside the frame without overhanging or sliding around.
Final Thoughts on Choosing Your Size
Selecting the right dimensions is the first step toward a better night of rest. I have learned that bigger is usually better for sleep quality, but only if it fits your room comfortably. Take your time to measure your space and think about how much room you really need to feel relaxed. Getting the right fit ensures your bedroom remains a sanctuary, so take your time to check what are the different sizes of mattresses before you buy.
I’m Derek Sutter, and I test sleep products for Bed Sleep Advisor from my home in Wyoming Ranchettes. Over the past 9 years, I’ve reviewed 60+ mattresses, everything from budget foam to premium hybrids, tracking firmness, motion isolation, and heat retention myself. Before this, I spent six years in furniture retail, where I watched customer after customer get overwhelmed by mattress shopping. That’s what I focus on now: real durability and comfort, not spec sheets.
