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The Ultimate Guide to Kids’ Mattress Sizes & Bed Sizes

May 13, 2024

Choosing the right bed size for your child is crucial for their comfort and growth. With so many options available, deciding which size is best can be overwhelming. This article will explore popular bed sizes for kids and provide essential tips to help you make an informed decision.

What Size Bed is Right for My Child?

Before diving into the specifics, let’s look at the most popular bed sizes for kids.

UK Kids’ Bed & Mattress Sizes

Bed Type

Mattress Size

Recommended Age


L 120cm x W 60cm

0 – 2 years old

Cot Bed

L 140cm x W 70cm

2 – 4 years old

Small Single

L 191cm x W 76cm

4+ years old


L 191cm x W 90cm

4+ years old

Small Double

L 191cm x W 120cm

8+ years old

These are averages, but exact measurements may vary, so when considering child’s mattress size make sure you look at the specific dimensions for the mattress that you’re interested in.

Mattress depth can vary, and the best mattresses for children will be thinner than full-sized mattresses.

How to Determine the Best Bed Size for Your Child

Now that we have an overview of the popular bed sizes let’s discuss how to determine the best one for your child. Several factors come into play, including age, height, and available space. Here are some guidelines to help you make the right choice:

  1. Consider your child’s age: A toddler bed is ideal for toddlers transitioning from a crib. These beds are smaller and have safety rails to prevent falls.

  2. Account for growth: Young children grow quickly, so choosing a bed size that provides enough room to stretch out comfortably is essential. A twin-size bed is a popular option for this age group.

  3. Accommodate personal space: Older children value their personal space. A full-size bed offers more room for them to move around and is suitable for growing teenagers.

  4. Consider the bedroom size: If you’re dealing with limited space, a space-saving bed, such as a bunk bed or a loft bed, might be the solution. These beds maximise vertical space while still providing a comfortable sleeping area.

Considering these factors, you can ensure your child has a bed that meets their needs and provides a comfortable and safe sleeping environment.

Bed Size for Toddlers

Toddlers are notorious for active movements during sleep. To keep them safe, opt for toddler beds with built-in safety rails. Smaller beds allow your child to transition from a crib without feeling overwhelmed. Toddler beds are generally for children aged 2-4 years.

When choosing a bed for your toddler, it’s crucial to prioritise safety. Toddler beds offer the perfect balance between comfort and security, ensuring that your little one can sleep peacefully throughout the night.

Bed Size for Young Children

As your child grows, their bed size needs to accommodate their increasing height and comfort requirements. A twin-size bed is a popular choice for young children. This bed size provides ample space for a child to sleep comfortably without feeling restricted.

A twin-size bed is an excellent option for young children as it offers enough space to sleep comfortably while still fitting well in most bedrooms. Choosing a mattress that provides adequate support for their growing bodies is essential.

Bed Size for Older Children

Older children, especially those in their pre-teen years, need more space to move around in their sleep. A full-size bed is an ideal option as it provides enough room for them to stretch out comfortably. This bed size can accommodate children well into their teenage years.

As children grow older, their sleep patterns and preferences change. A full-size bed gives them a comfortable and spacious sleeping area, ensuring a good night’s rest.

Bed Size for Teens and Young Adults

Your child’s growth spurt might require a larger bed size during the teenage years. A queen-size bed offers generous space and comfortably accommodates teenagers and young adults. Additionally, it provides room for sleepovers and offers the option of shared bedding.

A queen-size bed is an excellent investment for teenagers and young adults. It provides ample space for them to sleep comfortably and allows for flexibility when accommodating friends or siblings for sleepovers.

When to Transition Beds

From baby to toddler

It’s recommended that babies use cots from 0 to 2 years old, before moving to a toddler or cot bed. Cots are perfect for newborn babies, with protective railings and plenty of space to grow, but once they start to get bigger, you’ll want to upsize to ensure they’re comfortable.

Cot beds and toddler beds are perfect for transitioning towards larger kids’ beds. They’re more spacious than a cot for newborns and designed more like a regular bed, but with essential safety measures in place. Cot beds and toddler beds do require specific mattresses.

From toddler to preschool


Generally, little ones outgrow their cot or toddler bed at around 4 years old, and at that point they can move up to a small single. You could choose to go for a standard single bed at this age, but small singles still provide plenty of room for growth while saving you a bit of space in their room.

From age 4 onwards, it really comes down to their personal growth; you might choose to move them to a standard single bed if they’re growing quickly or stick with a smaller single until they’re nearing double digits. So long as they have space to grow and they’re comfortable – you don’t need to rush into upsizing.

Transitioning to adolescence

From age 8 and up is when they’ll likely start to hit some significant growth spurts, and at this time you might consider moving them to a small double bed to ensure their comfort. Once they get close to adolescence, it’s so important they have a supportive, spacious bed.

Mattress Sizes

Bunk Bed Mattress Sizes


If your children share a room with a bunk bed, it’s really important that you use mattresses specifically designed for bunks. There are some safety risks involved with bunk beds and using a specially designed mattress ensures their thickness and weight won’t pose any risks.

While the width and length of a bunk bed mattress remains the same as a regular bed – a single bunk bed mattress measures 191cm x 90cm – the depth of a bunk bed mattress must not exceed 17cm.

Bunk bed mattresses should be thinner and lighter than the average kids’ mattress. Explore our range of bunk bed mattresses to ensure both complete safety and complete comfort for your little ones.

Trundle and Futon Mattress Sizes

Like bunk beds, trundles need specific mattresses as they need to fit neatly underneath a full-sized bed. The same goes for futons, which need to be able to nicely fold into a seat when not being used as a bed. We have a range of trundle mattresses and futon mattresses at Aspace, designed with practicality and comfort in mind.

Single trundle mattresses typically measure 183cm x 77cm with a depth of no more than 14cm, but the size can vary. We also offer trundle bed mattresses that are 183cm x 90cm. Our futon mattresses are 190cm in length and between 75cm and 80cm in width depending on the style you choose.  

The Best Kids’ Bed Size to Save Space

As kids grow and explore their creativity and independence, a bit of clutter is pretty much unavoidable. With that in mind, you want to make sure you’ve got plenty of space for storage to keep things as tidy and organised as possible while ensuring they’ve also got space to play.

You don’t need to sacrifice comfort to be space-conscious, though, as luckily, there are many fantastic space-saving alternatives to the standard kids’ single bed that still ensure a comfy night’s sleep.

Essential Tips for Choosing the Right Bed for Your Child

Finally, when choosing the right bed for your child, a few additional tips can help ensure the best decision:

  • Involve your child: Let your child participate in the decision-making process. They will feel valued and more excited about their new bed.
  • Consider storage options: Beds with built-in compartments can be highly beneficial, especially if your child has a small room or lacks dedicated storage space.
  • Quality matters: Investing in a sturdy, durable bed will ensure it lasts years. Look for beds made from high-quality materials that can withstand your child’s playful activities.
  • Check safety features: Ensure your bed meets safety standards, especially for bunk or loft beds. Ensure that safety rails are in place and securely attached.

Choosing your child’s bed size significantly impacts their comfort and sleep quality. By considering their age, height, and preferences, you can ensure they have a bed that perfectly suits their needs. With this comprehensive guide and the answers to frequently asked questions, you can confidently make the best choice for your child’s sleep environment.

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The size of the bed your child needs depends on their age, height, and individual preferences. A toddler bed is usually the appropriate size for toddlers who have outgrown their cribs. These smaller beds, measuring around 70cm x 140cm, provide a secure sleeping space for young children. As your child grows, a single bed (90cm x 190cm) is typically sufficient to accommodate their increasing size. For older children, a small double bed (120cm x 190cm) offers more space for growing bodies, while teenagers and young adults may prefer a double bed (135cm x 190cm) or even a king bed (150cm x 200cm) for more comfort and room to stretch out.

At age 4, many children are ready to transition from a toddler bed to a larger one. A suitable bed for a 4-year-old is typically a single bed (90cm x 190cm). Single beds provide sufficient sleeping space for young children and allow them to sleep comfortably as they grow. Some parents may choose to keep their 4-year-olds in a toddler bed a little longer if they are comfortable and not showing signs of outgrowing it. Ultimately, the decision should be based on the child’s needs and readiness for a larger bed.

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