What are the UK Bed Sizes? Bed & Mattress Size Guide

Ever found yourself wondering, “Will a king-size bed even fit in my room?” or “How big is a king size vs double?” You’re not the only one - figuring out the right bed size can be surprisingly tricky, especially when space, comfort and budget all come into play.

In the UK, bed and mattress sizes follow standard measurements. However, they differ from those in Europe and the US, so it’s important not to rely on general sizing labels like "queen" or "king" without checking the exact measurements. In this guide, we’ll walk you through each UK bed size clearly, so you can shop with confidence and pick the one that’s just right for you.

Bed and Mattress Size Chart

Choosing the right bed starts with knowing the exact measurements. Below is a handy chart showing the most common UK bed and mattress sizes, with both imperial and metric dimensions. This makes it easy to compare options and see what fits your room - and your needs - best.

Cot

A cot is the smallest standard bed size in the UK and is designed specifically for babies and toddlers under the age of two. These beds are compact, with firm and supportive mattresses that prioritise safety and comfort during your child’s early growth stages. Measuring just 60 x 120 cm, cots are ideal when space is limited or when keeping your baby close by at night.

Pros: Cots offer several practical benefits for parents with very young children.

• Space-Saving Size: Their small footprint makes them easy to place in nurseries or next to the parents’ bed.
• Supportive Mattress: Cots typically feature a thick, firm mattress to help support a baby’s growing body.
• Lightweight and Easy to Move: Cots are generally easy to assemble and light enough to reposition without hassle.

Cons: Despite their usefulness, cots have a few limitations to consider.

• Short Lifespan: Babies quickly outgrow cots, usually by age two, so they’re a short-term solution.
• Limited Use: They are only suitable for infants and can’t be repurposed as your child grows.
• Variable Quality: Some cots may be made from lower-quality materials, especially in lower price ranges.

Best for: Babies and young toddlers in nurseries or compact bedrooms where space is limited.

Toddler Bed

Toddler beds are a practical next step once your child has outgrown their cot, typically suitable for little ones aged two to four. They offer a safe and comfy sleeping space while taking up very little room - ideal for compact bedrooms or flats. Though children outgrow them quickly, toddler beds are often an affordable and helpful solution for families navigating the cot-to-bed transition.

Pros: Toddler beds are designed to make life easier for both parents and growing children.

• Budget-Friendly Choice: They’re usually more affordable than full-sized beds, making them a cost-effective option.
• Compact and Convenient: Their narrow size makes them easy to fit into smaller rooms or shared spaces.
• Great for Transitioning: Toddler beds help bridge the gap between a cot and a full single bed, giving your child a familiar sleep environment

Cons: There are a few trade-offs to keep in mind with toddler beds.

• Kids Outgrow Them Quickly: Most children will need a larger bed by the time they’re four or five.
• Not Versatile: Toddler beds aren’t suitable for older children and don’t repurpose easily.
• Limited Styles and Sizes: There are fewer design options compared to standard beds, which can make it harder to find one that suits your space or aesthetic.

Best for: Young children aged two to four in small rooms, shared bedrooms or as a budget-friendly solution for early years.

Small Single Bed

Small single beds are narrower than a standard single, yet still offer the same length—making them a clever choice for tight spaces. Measuring 75 x 190 cm (2’6” x 6’3”), they’re often used in guest rooms, college dorms, compact offices, and children’s bedrooms. These beds are especially handy when you need to save on space without sacrificing a proper sleeping surface.

Pros: Small singles pack a lot of practicality into a slim frame.

• Great for Saving Space: Their narrow width makes them ideal for very small bedrooms or multi-use spaces.
• Ideal for Children: A reliable choice for younger children or those transitioning out of toddler beds.
• Easy and Affordable: Lightweight, cost-effective, and simple to move around or reposition when needed.

Cons: There are a few drawbacks to weigh up before buying.

• Too Small for Most Adults: These beds may not offer enough comfort or support for adult sleepers.
• Limited Longevity: As children grow, they’ll eventually need something bigger, making small singles a short-term solution.
• Fewer Style Options: Compared to standard single or double beds, you may find fewer designs and frames to choose from.

Best for: Young children as a 'first grown-up bed', and for use in small bedrooms, dorms, or guest spaces with limited floor area.

Single Bed

Single beds are one of the most versatile and commonly used bed sizes in the UK, offering a compact sleep solution without compromising on comfort. Measuring 90 x 190 cm (3’0” x 6’3”), they’re wider than small singles and provide enough space for solo sleepers of all ages—from growing children to adults. These beds are especially popular in children’s bedrooms, student accommodation, guest rooms, and small flats.

Pros: Single beds strike a balance between size and functionality for one person.

• Compact and Practical: Their modest footprint makes them perfect for small bedrooms, dorms, or multipurpose spaces.
• Great for Solo Sleepers: Offers a comfortable amount of room for one person to sleep soundly, especially side sleepers.
• Versatile for All Ages: From pre-teens to teenagers and even adults, single beds can accommodate various life stages.

Cons: Despite their practicality, single beds do have a few drawbacks.

• Limited Space to Stretch: Taller or restless sleepers might feel a bit restricted.
• Not Meant for Sharing: These beds aren’t suitable for couples or overnight guests sharing a bed.
• Visually Undersized in Large Rooms: A single bed might look too small in a spacious master bedroom, making the room feel unbalanced.

Best for: Solo sleepers - especially pre-teens, teenagers and adults in smaller bedrooms, guest rooms, or student accommodation.

Small Double / Queen Bed

A small double - also known as a Queen or Three Quarter - is a smart in-between option that’s wider than a single but slightly narrower than a standard double. Measuring 120 x 190 cm (4’0” x 6’3”), it provides generous space for solo sleepers and can work for two if you're happy to keep things cosy. It's a popular choice for guest rooms and smaller bedrooms where every inch counts.

Pros: Small doubles strike a balance between comfort and practicality.

• Space-Efficient Design: Its compact size works well in rooms that can’t quite accommodate a full double.
• Ideal for Solo Sleepers: Offers more room than a single without taking over the whole room.
• Great for Side Sleepers: Especially comfortable for solo sleepers who like to stretch out sideways.

Cons: There are a few points to consider if you’re thinking of going with this size.

• Can Be Tight for Two: Although technically big enough for couples, it may feel cramped for regular use.
• Less Widely Available: Bedding and frame options can be a bit more limited compared to standard doubles.
• Can Cost More: Surprisingly, small doubles can be pricier than standard single or even some double options.

Best for: One person who wants extra room, or couples in compact bedrooms where a full double won’t fit.

Double Bed

Double beds are one of the most popular bed sizes in the UK, measuring 135 x 190 cm (4’6” x 6’3”). They’re designed to comfortably accommodate two adults, offering a practical balance of space and comfort without being overly bulky. If you're after a wider sleeping area without adding extra length, a double is a solid choice for most medium-sized bedrooms.

Pros: Double beds offer comfort and versatility for a range of sleepers.

• Fits Most Couples: A practical option for two adults, offering enough width for shared sleeping.
• Great for Pet Owners: There’s room for a furry friend to snuggle in without too much disruption.
• Widely Available: With lots of choice in frames, styles, and bedding, it’s easy to find what suits your space and taste.

Cons: There are a few limitations to keep in mind with double beds.

• Can Be Heavy to Move: Larger frames and mattresses might be awkward to shift around.
• Tight Fit in Smaller Rooms: In compact bedrooms, a double bed may dominate the space and leave little room for anything else.
• Same Length as a Single: While wider, it doesn’t offer any additional length for taller sleepers.

Best for: Comfortably fitting two people in small to average-sized bedrooms without overcrowding the space.

King Size Bed

King size beds are a luxurious step up from a standard double, measuring 150 x 200 cm (5’0” x 6’6”). They’re both wider and longer, offering exceptional comfort for couples, tall individuals, or anyone who shares their bed with pets or children. With more room to stretch out, a king bed feels spacious - but it’s important to have a large enough bedroom to accommodate it properly.

Pros: King beds bring spacious comfort and style to larger bedrooms.

• Generous Sleeping Space: There's plenty of width for couples and extra length for taller sleepers.
• Family-Friendly: Perfect for co-sleeping families or those with pets who like to cuddle up.
• Suited to All Sleep Styles: Whether you’re a back, front or side sleeper, there’s enough space for everyone to rest comfortably.

Cons: With the size comes a few trade-offs.

• Takes Up a Lot of Room: It’s not suited to smaller bedrooms and can overwhelm compact spaces.
• More Expensive to Kit Out: Bed frames, sheets, and duvets for a king bed tend to cost more.
• Awkward to Move or Assemble: Due to their size and weight, moving or assembling a king bed can be a bit of a task.

Best for: Two people who want extra room, or taller individuals needing the extra length.

Super King Size Bed

The super king is the largest standard bed size available in the UK, measuring 180 x 200 cm (6’0” x 6’6”). It offers the same length as a king size but with an additional 30 cm of width, making it ideal for those who value space, comfort, and a luxurious sleeping experience. With ample room for couples, families, and even pets, it’s best reserved for large bedrooms that can handle its generous footprint.

Pros: Super king beds deliver ultimate comfort and sleeping space.

• Maximum Sleeping Area: Perfect for couples, tall sleepers, and anyone who enjoys plenty of space to spread out.
• Ideal for Co-Sleeping: Whether it’s children, pets, or both, there’s room for the whole family to climb in.
• Stylish in Large Rooms: Its grand size complements spacious bedrooms and adds a premium feel.

Cons: As impressive as it is, a super king comes with some considerations.

• Requires a Large Bedroom: These beds can dominate smaller spaces, so they’re best suited to larger rooms.
• More Expensive Bedding: Sheets and duvets for super king sizes cost more and can be harder to find.
• Heavy and Bulky: Moving or assembling a super king can be challenging due to its size and weight.

Best for: Two people in large bedrooms who value personal space and a premium sleeping experience.

How to Choose a Bed Size

Choosing the right bed size when shopping online can feel overwhelming—especially when you’re trying to balance comfort, room layout, and long-term practicality. Instead of just guessing what might work, use these clear guidelines to help make a confident decision from the comfort of home.

Do's

• Measure Your Bedroom Carefully: Use a tape measure to get the exact dimensions of your room, and leave at least 60 cm of clearance on each side of the bed so you can move around it easily.
• Account for Who Will Be Sleeping In It: If it’s just for you, a small double or double may be fine. For two adults, go for a king or super king if you’ve got the space - this helps reduce partner disturbance during the night.
• Check Your Height Against the Bed’s Length: If you’re 5’11” or taller, avoid beds that are only 190 cm long (like singles and doubles). Go for king or super king sizes, which measure 200 cm in length, to avoid cramped legs.
• Think About Layout, Not Just Size: Consider where windows, radiators, and wardrobes are placed. A large bed might technically fit the room but make the layout impractical.
• Plan for Bedding and Storage: Larger beds require larger duvets, sheets, and frames - which may be more expensive. Also check if you’d benefit from a divan or ottoman bed for extra storage.

Don’ts

• Don’t Assume Bigger Always Fits Better: Super king beds are luxurious but only suit rooms larger than 4.2 x 4.8 m. In smaller rooms, they’ll dominate the space and limit furniture placement.
• Don’t Reuse an Old Frame with a New Mattress: A mismatch in size can lead to sagging, poor support, or voided warranties. Always confirm that your frame matches the new mattress dimensions precisely.
• Don’t Choose Based on Looks Alone: That beautiful four-poster might look great online, but always check the actual dimensions - including the bed frame - which can take up more space than expected.
• Don’t Ignore Weight Capacity: Especially if two people will share the bed, make sure the mattress and frame support a combined weight of 500–800+ pounds depending on the size.
• Don’t Forget to Check Bedding Sizes Before You Buy: Sizes like small double and super king can be harder to shop for - check product availability and pricing for duvets, fitted sheets, and mattress protectors in that size.

Whether you’re furnishing a cosy box room or upgrading to something more spacious for two, knowing the exact measurements and what works best in UK homes can make all the difference. Now that you’ve got the full picture, you’re all set to make a well-informed choice that suits your space, budget, and sleep style. Browse our latest deals and let Wowcher help you sleep better!