4ft Bed vs 5ft Bed: Double vs King Size Explained
A 4ft small double bed measures 120x190cm while a 5ft king size bed measures 150x200cm, giving the king 30cm more width and 10cm more length. For couples choosing between them, the decision usually comes down to bedroom dimensions, mattress availability, and whether the extra space justifies the larger footprint long-term.
Size and Dimensions Compared
Use these exact UK measurements when planning your layout. A small double (also called 4ft) is 120cm wide by 190cm long. A king size (5ft) is 150cm wide by 200cm long. This means the king offers 75cm of width per person versus 60cm on the small double, and an extra 10cm in length for taller sleepers.
Remember EU sizes differ: an EU double is 140x200cm, so check your existing sheets and mattress protectors before buying. UK fire safety rules apply to all upholstered beds and mattresses sold here; always confirm the product meets BS 7177 standards.
| Size | Dimensions | Width per person | Typical room minimum |
|---|---|---|---|
| Small Double (4ft) | 120x190cm | 60cm | 2.4m x 2.9m |
| King (5ft) | 150x200cm | 75cm | 2.7m x 3.1m |
Room Fit and Floor Space
Measure your bedroom carefully before deciding. Allow at least 60cm clearance on each side for easy access and 90cm at the foot for changing sheets or opening doors. A 4ft small double fits more easily into smaller bedrooms or guest rooms, while a 5ft king needs roughly 0.5m² more floor area.
Practical checklist for room fit:
- Measure the room in cm, including awkward angles and radiator positions.
- Mark out both sizes on the floor with masking tape.
- Check door swing and wardrobe opening clearance.
- Consider future changes such as adding bedside tables or a chair.
If your room is under 2.6m wide, a small double bed is usually the safer choice. Larger rooms comfortably take a king; browse our full king size beds range.
Mattress Availability and Choice
Both sizes have good mattress availability in the UK, but the 5ft king offers more premium options. Small double mattresses are widely stocked for children’s and guest use, while king mattresses suit most couple preferences including memory foam, pocket sprung and hybrid types.
Check the product page for exact depth limits on any bed frame. For example, ottoman beds have maximum mattress depths stated by the maker.
Couples upgrading from a standard double (135x190cm) often move to a 5ft king for noticeably more shoulder room. See our king size mattresses or small double mattresses to compare current stock.
Long-Term Suitability for Couples
Think about how your needs may change over five to ten years. A 5ft king gives each sleeper more space to move without disturbing a partner and is better for taller adults or those who share with a pet. A 4ft small double works for couples who prefer closeness or have limited space, but some find it restrictive after a few years.
Decision rules:
- If both partners are over 180cm tall, choose the 5ft king for the extra 10cm length.
- If the bedroom is under 9m², the 4ft option is more practical.
- Consider storage needs; ottoman styles add useful under-bed volume in either size.
- Test similar mattresses in our Birstall showroom to feel the real difference in width.
For couples wanting storage, compare king size ottoman beds against small double ottoman beds.
Popular Frame Styles in Each Size
Both sizes are available in fabric, wooden, metal and upholstered frames. Small double frames tend to look more compact and are popular in children’s or guest rooms; many parents choose them for teenagers. King frames feel more substantial and are the most common choice for main bedrooms.
Look at practical styles such as ottoman, storage, or high-sleeper designs depending on your room. Flair, Noomi and Kyoto frames offer good build quality and clean lines. Always check the exact product page for dimensions, finishes and maximum mattress depth before ordering.
Which Size Should You Choose?
Use this rule: choose the 5ft king unless your room is too small or you prefer a cosier feel. Most couples who can fit a king prefer it long-term for better sleep quality and future-proofing. If space is tight, a well-chosen 4ft small double with a quality mattress still works well.
Visit our Birstall showroom to see both sizes made up with mattresses. Measure twice, buy once. For memory foam comfort in either size, explore our memory foam mattresses.
Our picks for this guide
- Kyoto Belle Ottoman Bed End Lift King Size (5ft) Natural – Offers generous 5ft king width for couples plus practical end-lift storage; ideal when choosing the larger size for long-term comfort.
- Flair Ava Small Double Fabric Ottoman Bed – Compact 4ft small double with useful storage; suits tighter bedrooms while still providing a quality frame for couples.
- Noomi Tera Solid Wood Small Double Bed (FSC-Certified) – Sustainable wooden 4ft frame that fits smaller rooms without sacrificing style when a king is too large.
- Kyoto Skandi Mid Century Bed King Size (5ft) Mid Oak – Stylish 5ft king frame with mid-century design; gives couples the extra space they need for better long-term suitability.
Frequently asked questions
Is a 4ft small double big enough for two adults?
A 4ft small double (120x190cm) gives each adult 60cm of width. It works for couples who like closeness or have limited bedroom space, but many find it snug after time. Taller adults may prefer the extra length of a 5ft king. Check the mattress depth limit on any frame you choose.
How much extra space does a 5ft king bed give?
A 5ft king measures 150x200cm compared with 120x190cm for a small double. This adds 30cm in width and 10cm in length, giving each person 15cm more shoulder room and better leg room. The larger size needs a minimum room of about 2.7m x 3.1m including clearance.
Can I use a standard double mattress on a 4ft small double bed?
No. A standard double mattress is 135x190cm and will overhang a 120cm wide small double frame. Always buy a mattress made for the exact bed size. Small double mattresses are readily available and usually cheaper than king size equivalents.
Which size is better for a small bedroom?
In rooms narrower than 2.6m or smaller than 9m², a 4ft small double is the better practical choice. It leaves more circulation space and still meets fire safety regulations. Measure carefully and allow 60cm on each side of the bed for access.
Are there storage options in both 4ft and 5ft sizes?
Yes. Ottoman styles with lift-up bases are available in both small double and king sizes. Check the exact maximum mattress depth on the product page so the frame functions correctly and complies with UK safety rules. King ottomans offer more absolute storage volume.