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Bunk beds are a popular solution for saving space while providing a practical and stylish sleeping arrangement in homes. One of the most important factors when choosing a bunk bed is its size, as it affects comfort, safety, and how well it fits into your room.
In this guide, we’ll walk you through the standard UK bunk bed mattress sizes, bed dimensions, safety guidelines, and space planning tips so you can confidently pick the right bed for your home. This guide will help you make an informed decision and choose a bunk bed that perfectly matches your room and needs.
Bunk beds are more than just stacked sleeping arrangements. Choosing the right size is essential, as it affects comfort, safety, and long-term practicality. An incorrectly sized bunk bed can lead to wasted space, poor sleep quality, or even safety hazards, especially for children.
Here are the main reasons why bunk bed sizes matter:
A mattress that doesn’t fit properly can leave gaps between the mattress and the frame, increasing the risk of slips or accidents. Too small a mattress may feel cramped, while one that is too thick can interfere with guardrails. The correct bunk bed size ensures enough room to stretch, proper posture support, and secure guardrails.
Many UK bedrooms are compact, and the wrong bunk bed size can overcrowd the room or block walking space. Choosing the right size helps maximise floor space and allows the room to remain functional. For example, a shorty or L-shaped bunk bed fits narrow rooms, while a high sleeper bunk frees up floor space for storage, a desk, or a play area.
UK mattress sizes differ from EU and US standards. A UK Single mattress (90 x 190 cm) won’t fit a US Twin or EU Single frame correctly. Matching mattress and frame dimensions prevents gaps, ensures proper support, and makes it easier to select compatible bedding and mattress protectors.
Most UK bunk beds are designed around a few standard mattress sizes, which makes it easier to select a frame that fits your room and needs. Knowing these sizes also ensures compatibility with sheets, bedding, and guardrails. Here’s a closer look at the common options:
This is the most common bunk bed mattress in the UK, making it ideal for children, teenagers, and even adults in compact rooms. Single mattresses are widely used in schools, hostels, holiday homes, and family bedrooms because they fit comfortably in standard two-tier bunk beds. Their dimensions offer enough space for a child to sleep comfortably without taking up too much room, making them highly versatile.
These mattresses are often found in triple sleeper bunks or bunk beds with wider bottom bunks. They provide extra space for two children or one adult on the bottom bunk, while a single mattress can be placed on the top. Small double and queen mattresses are ideal for families who want to combine comfort with space-saving solutions, especially in shared bedrooms or guest rooms.
Less common than singles, double mattresses are used in larger bunk beds designed for teenagers or adults. They offer a roomy sleeping area, often for a single sleeper who prefers extra space. Double mattresses are typically found in high sleeper bunks with desks or storage underneath, or in single-and-double bunk configurations where the bottom bunk is wider.
Mattress thickness is as important as length and width. For safety, top bunk mattresses should not exceed 15–20 cm in depth. Thicker mattresses reduce the height of guardrails, which can increase the risk of falls. Bottom bunk mattresses can be deeper if needed, but it’s always recommended to choose mattresses that fit snugly within the frame to prevent gaps and ensure overall stability.
Bunk beds come in various designs, from standard singles to multifunctional high sleepers. Knowing bunk bed sizes and bunk bed mattress size helps you pick a bed that fits your room and provides comfort and safety.
Before you buy a bunk bed, it is important to measure your room carefully to make sure the bed fits comfortably and safely. Here is what we recommend considering:
We always suggest leaving at least 75 cm of clearance between the top bunk and the ceiling. This ensures your child can sit up safely without bumping their head. Most UK homes with ceiling heights of 2.3 m or higher work well for standard bunk beds. Do not forget to measure the room’s length and width as well. This will help you see how much space the bed will take up and whether there is room for other furniture.
Some bunk beds come with built-in stairs, ladders, or slides. These features make climbing safer and more fun, but they also increase the bed’s footprint. We recommend factoring in an extra 40–60 cm in width or length depending on the design so your room does not feel cramped.
Safety always comes first. UK regulations require guardrails to extend at least 16 cm above the mattress. That means it is important to pick the correct mattress depth for your frame. Too thick, and the rails may not protect properly. Too thin, and the bed might feel less comfortable. We suggest sticking to the recommended mattress dimensions for your bunk bed to keep everything safe and cosy.
Not all bunk beds are built for the same users. When choosing the right size, it is important to consider who will use the bed and how much space is available in your room.
Some bunk beds come with built-in desks, shelves, or trundle beds. These designs are perfect for growing families or shared rooms, as they maximise floor space while providing extra functionality. For example, a bunk bed with a trundle can sleep an extra child for sleepovers, while high sleepers free up space underneath for a study area or wardrobe.
All bunk beds sold in the UK must comply with the BS EN 747 safety standard. This ensures that the bed frame, mattress support, and guardrails meet strict safety requirements. Following these guidelines helps prevent accidents and keeps children and adults safe while using bunk beds.
Top bunk mattresses should not exceed 15–20 cm in thickness. Choosing a mattress within this range ensures that the guardrails remain at least 16 cm above the mattress surface, which is required for safety. Guardrails help prevent falls during sleep and must be securely attached to the bed frame. Bottom bunk mattresses can be slightly deeper if needed, but they should still fit snugly within the frame to avoid gaps that could cause discomfort or accidents.
Safety rules also recommend age limits for bunk bed use:
To make it easier to compare the most common bunk bed and mattress sizes in the UK, we’ve put together this quick reference table. It summarises mattress dimensions and frame sizes so you can see all the key information at a glance.
| Type | Top Mattress Size (cm) | Bottom Mattress Size (cm) | Frame Dimensions (L x W x H in cm) |
| Standard Single | 90 x 190 | 90 x 190 | 200–210 x 95–100 x 160–175 |
| Small Single / Shorty | 75 x 175 or 80 x 180 | 75 x 175 or 80 x 180 | 75–80 x 175–180 x 150–160 |
| Double / Queen | 90 x 190 | 120–140 x 190 | 210–220 x 120–140 x 165–175 |
| Triple | 90 x 190 | 120 x 190 | 230–240 x 200 x 165–175 |
| Quad | 90 x 190 | 90 x 190 (x2) | 240–350 x 200–220 x 165–175 |
| High Sleeper | 90 x 190 | N/A (space underneath) | 240 x 100–120 x 175 |
| Single & Double | 90 x 190 | 140 x 190 | 240 x 140 x 175 |
| Single & Double Trundle | 90 x 190 | 140 x 190 + trundle | 240 x 140 x 175 (+ extra 100 cm for trundle) |
We hope this guide has helped you understand bunk bed sizes, and mattress options. The key to choosing the right bed is to match the mattress size to the frame, measure your room dimensions and ceiling height, and follow UK safety standards for mattress thickness and guardrails.
At MK Furnishings, we offer a wide range of bunk beds designed with quality, safety, and practicality in mind. Whether you are looking for a single, double, triple, or high sleeper, our beds help maximise space while keeping bedrooms comfortable and organised.
With the right planning, a bunk bed can provide safe, stylish, and space-efficient sleeping arrangements for children, teenagers, or adults. If you have any questions or need help choosing the perfect bunk bed, our team at MK Furnishings is here to help. Happy planning and happy sleeping!
Most bunk beds in the UK are designed to fit a single mattress measuring 90 x 190 cm. This size works well for children, teenagers, and even adults in guest rooms or smaller bedrooms.
While the single mattress is the most common, some bunk beds are designed to fit a small double measuring 120 x 190 cm, a full double at 140 x 190 cm, or even a combination of sizes for top and bottom bunks. Always check the bed frame specifications before purchasing.
A standard single bunk bed usually fits a 90 x 190 cm mattress. Small single bunks measure around 75 x 175 cm or 80 x 180 cm. Small double bunks use a 120 x 190 cm mattress, and full double bunk beds are generally 135–140 x 190 cm. The overall bed frame dimensions may be slightly larger to accommodate safety rails and structure.
For safety, the mattress on the top bunk should be between 15 and 20 cm thick. This ensures the guardrails provide proper protection and prevent falls.
We recommend a ceiling height of at least 2.1 to 2.3 meters. This provides enough clearance above the top bunk so sleepers can sit up safely without hitting their head.
Kyle Kane
Owner
Kyle Kane is Co-Owner of MK Furnishings, a family-run business based in UK that specializes in high-quality custom kids’ bunk beds, including triple, double, single, and themed designs. Since launching the company in 2016 alongside his brother-in-law, Kyle has helped deliver and assemble thousands of beds across the UK, Ireland, and beyond. Focused on customer satisfaction, Kyle leads a hardworking team that handles every step from ordering to delivery ensuring a smooth and professional service. His commitment to quality craftsmanship and reliable support has earned MK Furnishings a strong reputation and growing customer base throughout the region.
Yes, memory foam mattresses are good because they provide pressure-relieving, body-contouring comfort and excellent motion isolation that reduces partner disturbance. By adapting to body shape,
Yes, bunk bed mattresses are different from regular mattresses because of their reduced thickness, usually around 5 to 8 inches (12-20 cm), to maintain guardrail
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