Find Your Perfect Mattress Size

Choosing the right mattress size is about more than measurements. It’s about creating a solid foundation for quality sleep, lasting comfort, and overall wellbeing. Whether you’re furnishing a first apartment, upgrading a primary bedroom, or planning a family-friendly sleep setup, understanding UK and Irish mattress sizes is the essential first step toward better rest.

At Snooze Mattress & Wellness, we help customers across the UK and Ireland find the perfect mattress for their lifestyle, space, and sleep style. This guide will walk you through every standard size, show you how they compare, and help you make a confident decision before you buy.

Mattress Sizes Explained

Below, we break down each mattress size with its best uses, room recommendations, and lifestyle fit — plus links to explore matching options in our collection.

💡 Pro tip: UK and Irish mattress sizes are the same, but they differ slightly from European and U.S. sizes. Always double-check bed frame compatibility before you buy.

Small Single Mattress – 75 x 190 cm (2ft 6in x 6ft 3in)

Best for: Young children, very narrow rooms, box rooms
A compact footprint that frees up floor space for storage or study. Still supports a full-size sleeper in a pinch.

Small single room size tip: Works in rooms from ~1.9m x 2.4m.

Single Mattress – 90 x 190 cm (3ft x 6ft 3in)

Best for: Kids’ bedrooms, guest rooms, compact spaces

A single mattress is perfect for solo sleepers, growing children, and smaller bedrooms. It’s the most space-efficient size and ideal for standard box rooms or guest spaces. Despite its smaller footprint, our single mattress collection still delivers premium support and comfort.

Single room size tip: Works best in rooms at least 2m x 2.5m.

Long Single Mattress – 90 x 200 cm (3ft x 6ft 6in)

Best for: Taller teenagers, spare bedrooms, adjustable beds

A long single mattress is similar in width to a standard single but adds 10cm in length, making it a smarter choice for taller sleepers. It’s also commonly used in adjustable base setups as part of a split king configuration. Explore our long single options for growing teens or flexible guest room layouts.

Long single room size tip: Best in spaces around 2.1m x 2.6m or larger.

Small Double Mattress – 120 x 190 cm (4ft x 6ft 3in)

Best for: Solo sleepers who like more space, compact couple setups

Also known as a “four-foot” mattress, the small double bridges the gap between single and double. It’s a versatile choice for single sleepers who want more room or couples furnishing a smaller apartment. View our small double mattresses for a balance of comfort and practicality.

Small double room size tip: Ideal for rooms around 2.5m x 2.8m.

Long Small Double – 120 x 200 cm (4ft x 6ft 6in)

Best for: Tall solo sleepers, compact bedrooms needing extra length
Keeps the slim 120 cm width of a small double but adds 10 cm of legroom. Great in narrow Victorian/period rooms.

Long small double room size tip: Aim for 2.5m x 2.9m.

Double Mattress – 135 x 190 cm (4ft 6in x 6ft 3in)

Best for: Most couples, master bedrooms, guest rooms

The most popular size across the UK and Ireland, a double mattress offers a comfortable space for two without taking over the entire room. It’s a great choice for couples or anyone looking for a versatile size that fits most bedrooms. Explore our double mattresses to find the right comfort level and support.

Double room size tip: Best in rooms at least 2.8m x 3m.

Long Double – 135 x 200 cm (4ft 6in x 6ft 6in)

Best for: Taller couples, guest rooms with extra length
Same width as a standard double with extended length for taller sleepers. Easier bedding fit than mixing EU sizes.

Long double room size tip: About 2.9m x 3.1m is comfortable.

King Mattress – 150 x 200 cm (5ft x 6ft 6in)

Best for: Couples who value space, main bedrooms, luxury comfort

A king size mattress offers more room for both sleepers and significantly reduces partner disturbance. It’s the most recommended size for couples who want maximum comfort without overwhelming their space. Shop our king size mattresses for the ideal mix of comfort and space.

King room size tip: Works best in bedrooms 3m x 3.3m or larger.

Super King Mattress – 180 x 200 cm (6ft x 6ft 6in)

Best for: Families, co-sleepers, larger bedrooms

A super king mattress is all about luxury and space. It’s perfect for couples who love to spread out or families with little ones who occasionally crawl into bed. For those seeking hotel-level sleep at home, browse our super king collection.

Super king room size tip: Requires a room size of at least 3.5m x 3.5m.

Euro King – 160 x 200 cm (5ft 3in x 6ft 6in)

Best for: Couples wanting more width than UK King, EU bed frames
Sits neatly between UK King and Super King. Common in EU furniture ranges; check frame and sheet compatibility.

Euro king room size tip: Target 3.2m x 3.4m or larger.

Emperor Mattress – 200 x 200 cm (6ft 6in x 6ft 6in)

Best for: Master suites, luxury homes, maximum comfort

The largest standard mattress size available in the UK and Ireland, the emperor mattress turns your bedroom into a luxury sleep retreat. It’s perfect for those who value space above all else or want to future-proof their master bedroom setup. Discover our emperor mattress options for the ultimate in spacious sleep.

Emperor room size tip: Works best in rooms 4m x 4m or larger.

How to Choose the Right Mattress Size

Choosing your ideal mattress size isn’t just about the dimensions — it’s about how you live, sleep, and use your space. Here’s what to consider before making your decision:

1. Think About Your Room Size

Leave at least 60cm of walking space around the bed on all sides. If you’re furnishing a smaller room, a small double or standard double might be more practical than a king or super king.

2. Consider Who’s Sleeping on It

• Single sleepers: Single, long single, or small double

• Couples: Double or king minimum

• Co-sleeping families: Super king or emperor

3. Budget vs. Longevity

Larger mattresses typically cost more, but they offer better long-term comfort and value. Our flexible payment options make it easier to invest in the size that truly suits your lifestyle.

Split Mattresses: Custom Comfort for Couples

If you and your partner have different sleep preferences, a split mattress can be a game-changer. Rather than compromising on firmness or support, a split system lets each person customise their side of the bed without affecting the other. This is especially useful for couples with different body types, temperature preferences, or medical needs.

Split mattresses are most commonly available in King or Super King sizes, consisting of two separate mattresses placed side by side. They’re also ideal for adjustable bed bases, allowing each side to move independently.

Why consider a split mattress:

• Each sleeper chooses their ideal firmness or material

• Significantly reduces partner disturbance

• Perfect for adjustable bed systems

• Future-proofs your sleep setup as needs change

Explore our split mattress options to learn how personalised comfort can transform your sleep. Couples love this solution provided by Snooze.

Recommended Room Sizes for Each Mattress

Knowing the minimum recommended room size helps you avoid a crowded or uncomfortable layout. Use this guide to plan your bedroom space before choosing a mattress size:

Mattress Size Recommended Minimum Room Size Single 2.0m x 2.5m Long Single 2.1m x 2.6m Small Double 2.5m x 2.8m Double 2.8m x 3.0m King 3.0m x 3.3m Super King 3.5m x 3.5m Emperor 4.0m x 4.0m

💡 Pro tip: Always leave at least 60cm of space around your bed for easy movement, bedside tables, and wardrobe access.

UK vs EU vs US Mattress Sizes: What’s the Difference?

Mattress sizes aren’t universal — and understanding the differences can save you costly mistakes when ordering bed frames or bedding from abroad.

• UK & Ireland: Follow the same sizing standards. A “King” mattress is 150 x 200 cm.

• European sizes: Slightly longer and wider. A European King is typically 160 x 200 cm.

• U.S. sizes: Use different naming altogether. A U.S. Queen is roughly 152 x 203 cm, close to a UK King, while a U.S. King is larger at 193 x 203 cm.

Always double-check measurements when mixing European or U.S. bed frames with UK or Irish mattresses.

Frequently Asked Questions About Mattress Sizes

Are mattress sizes standard in the UK and Ireland?

Yes, UK and Irish mattress sizes are the same and standardised across most manufacturers. This means a King size mattress from one brand will match a King bed frame from another, as long as they follow UK sizing.

What size mattress is best for couples?

A King size (150 x 200 cm) is the most popular choice for couples in the UK and Ireland, offering a great balance of space, comfort, and room fit. If you want even more room or co-sleep with children, consider a Super King (180 x 200 cm).

What’s the difference between a King and Super King mattress?

A Super King is 30 cm wider than a King mattress, giving each sleeper more personal space. It’s ideal if you value extra room or often have children or pets sharing the bed.

What size is best for small bedrooms?

For compact bedrooms, a Small Double (120 x 190 cm) offers extra sleeping space without overwhelming the room. Always measure first — you’ll want at least 60 cm of space around the bed.

Can I use European or U.S. bedding with a UK mattress?

Not always. European and American sizes are different from UK standards, so fitted sheets and bed frames may not align properly. Always check dimensions before buying accessories from abroad.

Will a King or Super King mattress fit up my stairs?

Most King and Super King mattresses will fit up standard staircases, but tight corners or narrow spaces can be tricky. This is exactly why many couples choose a "split" mattress. Not only can you customise the comfort level on each side of the bed, it's also much easier to fit up a twisty staircase.

Ready to Find Your Perfect Mattress?

The right mattress size transforms more than just your sleep — it changes how you live, rest, and recover. Whether you’re furnishing a compact apartment or designing a luxury master suite, Snooze Mattress & Wellness helps you make the perfect choice with confidence.

👉 Next steps:

• Shop our entire mattress collection to compare sizes and comfort levels

• Book a free consultation with our sleep experts to get personalised recommendations

• Visit our Cork showroom to try different sizes in person

Your best night’s sleep starts with the right size. Let Snooze Mattress & Wellness help you find it.