Mattress Sizes Guide for Every UK Bedroom

A bed can look perfect online, then feel far too large once it is in the bedroom. This mattress sizes guide sets out the standard UK mattress dimensions and, just as importantly, how to choose a size that suits your room, sleep habits and bed style.

The right mattress should give you enough space to sleep comfortably without making everyday life around the bed awkward. Measure carefully before you order, especially if you are choosing an upholstered frame, ottoman bed or statement headboard, as the finished bed will be larger than the mattress itself.

UK mattress sizes at a glance

| Mattress size | Dimensions in cm | Dimensions in feet and inches | Best for |
|---|---:|---:|---|
| Small single | 75 x 190 cm | 2'6" x 6'3" | Young children, narrow rooms and bunk beds |
| Single | 90 x 190 cm | 3' x 6'3" | Children, teenagers, guest rooms and solo sleepers |
| Small double | 120 x 190 cm | 4' x 6'3" | One person wanting extra room or compact couples' rooms |
| Double | 135 x 190 cm | 4'6" x 6'3" | Couples and most standard bedrooms |
| King size | 150 x 200 cm | 5' x 6'6" | Couples wanting more space and taller sleepers |
| Super king | 180 x 200 cm | 6' x 6'6" | Larger bedrooms, families and luxurious comfort |

These are standard UK mattress measurements. Sizes can vary slightly between manufacturers, particularly with handmade, custom or deeper premium mattresses, so always check the product specification before buying fitted sheets or a new bed frame.

Mattress sizes guide: choosing for your bedroom

A tape measure is the most useful shopping tool you can have. Measure the clear floor area where the bed will sit, then account for wardrobes, drawers, radiators, doors and windows. It is easy to focus on whether the mattress fits while forgetting that you need room to walk around it, make the bed and open storage.

As a practical rule, aim for around 60 cm of clearance along the sides of the bed where possible. That may not be realistic in every compact bedroom, but it highlights why moving from a double to a king size can change the whole layout. A king mattress is only 15 cm wider than a double, yet the bed frame, upholstered side rails and headboard can make the overall footprint noticeably bigger.

If you are selecting an ottoman bed, check the opening space too. End-opening designs need clear room at the foot of the bed, while side-opening options need usable space on the chosen side. Storage beds are an excellent way to make a smaller bedroom work harder, but access needs planning rather than guesswork.

Small single mattresses: 75 x 190 cm

A small single is a smart choice for younger children, compact box rooms and beds with limited-width frames. It saves 15 cm compared with a standard single, which can make a real difference in a narrow room. However, it is not the best long-term option for a rapidly growing teenager or an adult who needs more room to move.

Single mattresses: 90 x 190 cm

The UK single remains one of the most versatile mattress sizes. It suits children moving up from a smaller bed, teenagers, guest rooms and solo adults with limited bedroom space. Single divans and upholstered beds are also practical for creating matching twin beds in a shared room.

For taller sleepers, length matters as much as width. At 190 cm long, a single may feel restrictive if you are well over six feet tall. In that case, a longer king size mattress or a made-to-measure option may be more comfortable.

Small double mattresses: 120 x 190 cm

Often called a three-quarter bed, a small double gives a single sleeper generous room without taking over the bedroom. It is a popular choice for teenagers, first flats and guest rooms where a standard double would be too imposing.

Two adults can use a small double occasionally, but it is tight for every night. Each person gets only 60 cm of sleeping width, which is less space than a standard single mattress. It can work where space is genuinely limited, but couples who value uninterrupted sleep will usually be happier with at least a double.

Double mattresses: 135 x 190 cm

A double is the familiar choice for many UK homes and fits a broad range of bed frames, divans and bedding. It is a practical middle ground for couples, particularly in average-sized bedrooms, and it offers more sleeping room than a small double without the larger footprint of a king.

The compromise is personal space. A double gives each adult 67.5 cm of width, so it can feel cosy rather than spacious, especially if one or both sleepers turn frequently, share the bed with a child or pet, or simply prefer room to stretch out.

King size mattresses: 150 x 200 cm

A king size mattress adds 15 cm of width and 10 cm of length compared with a double. Those figures may sound modest, but the extra space is often what makes a bed feel more comfortable for two. The added length is particularly welcome for taller sleepers.

A king size is a strong choice for a main bedroom if the layout allows it. It also gives you more freedom to choose a deeper, luxury mattress without making the bed feel cramped. Before upgrading, measure the route into your home as well as the bedroom. Tight staircases, turns and loft conversions can affect which bed base or frame is most practical.

Super king mattresses: 180 x 200 cm

For generous sleeping space, a super king is hard to beat. It is the same length as a king but 30 cm wider, giving each person the equivalent width of a standard single mattress. That makes it an excellent option for couples with different sleep schedules, light sleepers and anyone who wants a true hotel-style feel at home.

It does need a suitably sized room. A super king bed can dominate a small bedroom, particularly with a wide winged headboard or bulky bedside cabinets. It is also worth considering the cost and availability of super king bedding, although it is widely stocked in the UK.

Remember the bed frame is bigger than the mattress

Mattress dimensions describe the sleeping surface, not the complete bed. A simple divan is usually close to the mattress size, while an upholstered bed frame may extend several centimetres on each side. Sleigh beds, storage beds with substantial side rails and beds with oversized headboards can take up considerably more space.

Always look for the external dimensions of the specific bed design. This matters when positioning bedside tables, fitting a bed between alcoves or choosing a bed for a room with a chimney breast. If you are creating a bespoke bed, you can also consider details such as headboard height, fabric colour and storage direction around the room's practical needs.

Match mattress size to how you sleep

Room size sets the limit, but your sleep habits should guide the final decision. If you sleep alone and like room to spread out, a small double may feel far more luxurious than a single. If you share a bed and one person is restless, the step up from a double to a king can be worthwhile.

Mattress construction matters too. A pocket sprung mattress can reduce the feeling of movement travelling across the bed, while memory foam, hybrid, cool gel and latex options each create a different feel. A larger mattress does not automatically solve comfort issues if the tension, support or material is wrong for your body and sleeping position.

For couples with very different comfort preferences, consider whether a larger bed gives you more choice. A super king can sometimes be paired with two separate 90 x 200 cm mattresses, allowing each sleeper to select their preferred feel. This is not right for everyone, as there may be a join in the middle, but it can be useful where support needs are very different.

Check bedding before you buy

Standard UK fitted sheets are made for standard UK mattress sizes, but depth is just as important as width and length. Deep pocket sprung, pillow-top and hybrid mattresses may need extra-deep fitted sheets. Measure from the base to the highest point of the mattress, including any topper you plan to use.

Duvet sizes are more flexible. Many couples choose a king size duvet on a double bed for extra coverage, while a super king duvet on a king bed can feel particularly generous. The mattress should fit the bed exactly, but your duvet can be sized around the level of comfort you prefer.

A new bed is a long-term part of your home, so choose the biggest mattress size that fits your room comfortably and supports the way you sleep. If you are unsure between two sizes, seeing the proportions in person and speaking to a bed specialist can make the decision much easier.