Single vs King Single Mattress: Which One Still Works in Five Years?
Choosing between a Single and King Single mattress is often treated as a simple room-size decision. The Single takes up less space, while the King Single is larger.
But the more useful question is this: which size will still work for the sleeper and the room several years from now?
A Single can be practical for a child, compact bedroom or occasional guest. A King Single adds useful width and length without taking up as much floor space as a Double or Queen. That extra space may matter as a child grows, when a teenager needs more room or when the bed must also accommodate an adult guest.
Neither size is automatically better. The right choice depends on the sleeper’s height, the bedroom layout, other furniture, future use and the complete cost of the mattress, base and bedding.
Single vs King Single Mattress Dimensions
Using rounded Australian dimensions, a standard Single mattress is approximately 92 cm wide by 188 cm long. A King Single is approximately 107 cm wide by 203 cm long.
| Comparison | Single mattress | King Single mattress |
|---|---|---|
| Approximate width | 92 cm | 107 cm |
| Approximate length | 188 cm | 203 cm |
| Width difference | More compact | Approximately 15 cm wider |
| Length difference | Shorter standard length | Approximately 15 cm longer |
| Often considered for | Children, compact rooms and occasional guests | Growing teenagers, taller solo sleepers and regular adult guests |
These are rounded mattress measurements. Small variations can occur between manufacturers and products, and the bed base or frame may extend beyond the mattress. Always check the dimensions of the exact products being considered.
For the broader range of Australian dimensions, refer to the Best Beds Bed Size Guide.
The Five-Year Test
A mattress is not usually purchased for a few months. Before choosing the smaller size, imagine how the room and sleeper may change over the next several years.
Ask:
- Is the sleeper likely to grow significantly?
- Will the room remain a child’s bedroom?
- Could the bed later be used by a teenager or adult?
- Might the room become a guest room, study or multipurpose space?
- Could the bed need to move to a smaller room or another property?
- Will replacing the mattress, base and bedding later cost more than choosing the larger size now?
This does not mean every young child needs a King Single. It means the future use of the bed deserves as much consideration as the current use.
When a Single Mattress May Be the Better Choice
A Single mattress may be more practical when conserving bedroom space is the main priority.
The Bedroom Is Compact
The narrower and shorter footprint can leave more space for a desk, toy storage, drawers, a wardrobe or a clearer walking path.
This can be especially important where one room must accommodate several functions. A bed that technically fits but blocks furniture or dominates the room may not be the most practical choice.
The Bed Is for a Younger Child
A standard Single may provide sufficient room for a younger sleeper while keeping the bedroom open and easy to organise.
Consider how soon the child may outgrow the length or want more width. The answer will vary between households, so avoid choosing purely according to age.
The Room Is Used Only Occasionally
A Single can work well in a compact guest room used mainly by children or occasional solo visitors. It may leave enough floor space for the room to serve another purpose when no guest is staying.
Moving Flexibility Matters
A smaller mattress and base may be easier to move through narrow hallways, staircases and doorways. It may also fit a wider variety of bedrooms if the household moves later.
Browse the current Single mattress collection after confirming that the standard length suits the intended sleeper.
When a King Single Mattress May Be the Better Choice
A King Single may be worthwhile when the bed is intended to remain useful through several stages of life.
The Sleeper Is Growing
The additional length can be particularly relevant for a teenager approaching adult height. The added width also provides more space for changing position during the night.
Choosing a King Single earlier may reduce the likelihood of replacing the entire setup simply because the sleeper has outgrown a standard Single.
The Bed May Be Used by an Adult
A King Single can provide a more generous solo sleeping area for an adult without requiring the width of a Double or Queen.
This may make it suitable for a guest room expected to accommodate adult visitors regularly.
You Need Length Without a Wide Bed
A King Single has approximately the same standard length as a Queen or King mattress while remaining much narrower.
This can make it useful for a taller solo sleeper in a bedroom that cannot comfortably accommodate a larger couple’s size.
The Room Will Change Purpose Later
A child’s room may eventually become a teenager’s bedroom, adult guest room or study with a permanent spare bed. A King Single may remain useful through those changes.
Review the available King Single mattresses after measuring the complete room and access route.
Is the Extra 15 cm of Width Noticeable?
Fifteen centimetres may not sound substantial when written on a product page, but it can be noticeable on a mattress used by one person.
The added width may provide:
- more space to change sleeping position;
- additional room around the shoulders and arms;
- a less confined feel for a teenager or adult;
- more flexibility when sitting on the bed to read or use a device.
That same width also occupies more bedroom floor space. Mark both mattress footprints on the floor with removable tape before deciding. Then add the external dimensions of the intended base or frame.
The Length Difference May Matter More Than the Width
The King Single’s extra length is one of the most important differences between the two sizes.
A pillow occupies part of the mattress length, so the sleeper’s height alone does not show how much usable space remains at the foot of the bed. Sleeping position also matters. Someone who stretches out may use more length than a person who normally sleeps curled slightly.
Check the sleeper’s position on the current mattress rather than relying only on their standing height. If their feet are already close to the end, moving to another standard Single may provide no meaningful improvement.
Measure the Complete Bedroom
Do not choose a mattress size from the wall-to-wall room dimensions alone.
Measure and record:
- the proposed mattress position;
- the external bed-base or frame dimensions;
- bedside-table space;
- wardrobe and drawer clearance;
- the swing of the bedroom door;
- the position of power points and windows;
- space required for a desk or study chair;
- the normal walking route through the room.
A King Single may fit between two walls but still make the room inconvenient if it blocks a drawer or leaves no usable study space.
A Single may be the better room-planning decision when the extra King Single width prevents the bedroom from working properly.
Check the Base or Frame Separately
The mattress size is not necessarily the total bed size.
An upholstered frame can add width through side rails and length through a headboard or foot section. A simple bed base may remain closer to the mattress footprint, but its exact dimensions should still be checked.
Best Beds has dedicated bed-base options, including selected Single and King Single sizes. Availability and dimensions vary by product.
When changing mattress size, the existing base usually cannot be reused because the mattress and foundation dimensions must match.
Remember the Bedding
Moving from Single to King Single generally means changing more than the mattress and base.
The household may also need:
- King Single fitted sheets;
- a suitable mattress protector;
- appropriately sized bedding;
- a different bed frame or base.
Include the full setup when comparing the cost of choosing a Single now and replacing it later against choosing a King Single from the beginning.
The lower initial cost of a smaller bed may still be the right decision, particularly when the room is temporary or space is limited. The important point is to compare the complete lifecycle rather than only the mattress price.
Moving and Property Access
A King Single is still a practical solo size, but it is longer and wider than a standard Single.
Before ordering, check:
- bedroom and property doorways;
- hallway corners;
- stairs and landings;
- apartment lifts;
- the size and rigidity of the base or frame components.
A mattress may flex to some degree, while a base, headboard or frame section may be more rigid. Measure the entire delivery route rather than assuming that anything intended for a bedroom will automatically reach it.
Single vs King Single by Room and Sleeper
| Situation | Starting point to consider |
|---|---|
| Young child in a compact bedroom | Single, particularly where floor space is important |
| Growing teenager | King Single for additional width and length |
| Taller solo adult | King Single or another 203 cm-long mattress size |
| Occasional child guest | Single may be sufficient |
| Regular adult guest | King Single may provide greater flexibility |
| Multipurpose bedroom or study | Choose according to the floor space required for the room’s other function |
| Household expecting to move | Consider both future bedroom sizes and ease of handling |
These are planning prompts, not universal rules. Measure the room and consider the actual sleeper before deciding.
Simple Decision Checklist
A Single may be the better choice if:
- the bedroom is genuinely compact;
- the bed is mainly for a younger child;
- the room needs space for a desk, storage or play area;
- the bed will be used only occasionally;
- future moving flexibility is a priority.
A King Single may be the better choice if:
- the sleeper is tall or still growing;
- the bed should remain useful into the teenage or adult years;
- adult guests will use the room;
- additional personal sleeping space is valuable;
- the bedroom accommodates the larger complete bed comfortably.
Compare Single and King Single Options at Best Beds
Best Beds is a mattress and bedroom furniture retailer in Epping, Melbourne. The current range includes selected mattresses and bed bases in Single and King Single sizes, with availability varying by product.
Browse the relevant size collections online and bring your room measurements when comparing options. Check the Best Beds Contact page for current Epping location, directions and opening information before travelling.
The Mattress Buying Guide can also help you compare comfort, construction and foundation requirements after selecting the correct size.
Conclusion
A King Single is approximately 15 cm wider and 15 cm longer than a standard Single when using rounded Australian dimensions.
The Single saves bedroom space and may be entirely suitable for a child, compact room or occasional guest. The King Single provides more room for a growing teenager, taller solo sleeper or regular adult guest.
Choose by looking beyond today. Measure the complete bed, consider how the sleeper and room may change, and compare the cost and practicality of the entire setup.
Frequently Asked Questions
What is the difference between a Single and King Single mattress?
A standard Australian Single is approximately 92 cm wide by 188 cm long. A King Single is approximately 107 cm wide by 203 cm long, using rounded dimensions.
Is a King Single suitable for an adult?
It can be. A King Single provides the same approximate length as a Queen or King while remaining designed for one sleeper. Comfort and suitability still depend on the individual mattress and sleeper.
Should I buy a Single or King Single for a teenager?
A King Single may provide more useful width and length for a growing teenager, but a Single may be more practical where the bedroom is compact.
Can a Single mattress fit on a King Single base?
No. The mattress and base should be the same size. A Single mattress would not properly cover a King Single foundation.
Is a King Single the same length as a Queen?
Yes, both are generally approximately 203 cm long in Australia. The Queen is substantially wider because it is designed to accommodate more sleeping space.
