A King mattress is 183 × 203 cm in Australia — 30 cm wider than a Queen, and exactly the same length. It gives each of two sleepers about 91 cm of width, which is roughly the width of a Single bed each. You want a bedroom of about 3.3 × 3.4 m or larger to walk around it comfortably.
Below: the exact dimensions, how a King compares to a Queen and a Super King, whether your room and your doorways can take one, and what to check on bedding and bases.
King bed dimensions
A King mattress is 183 cm wide and 203 cm long. That is the standard Australian King size.
| Size | Width | Length |
|---|---|---|
| Single | 92 cm | 188 cm |
| King Single | 107 cm | 203 cm |
| Double | 138 cm | 188 cm |
| Queen | 153 cm | 203 cm |
| King | 183 cm | 203 cm |
| Super King | 203 cm | 203 cm |
A useful way to picture it: two Singles side by side come to 184 cm, which is within a centimetre of a King. If you have ever pushed two single beds together in a holiday house, that is roughly the width you slept on.
King vs Queen
A King is 30 cm wider than a Queen. The length is identical at 203 cm. So the upgrade is entirely about width.
| Queen | King | |
|---|---|---|
| Width | 153 cm | 183 cm |
| Length | 203 cm | 203 cm |
| Width per person | About 76 cm | About 91 cm |
| Room needed | About 3 × 3.4 m | About 3.3 × 3.4 m |
That 15 cm each is more noticeable than it sounds, particularly if one of you moves around at night or a child or dog joins you. But because the length does not change, a King does nothing extra for a tall sleeper — a Queen is already full length.
Go King if two adults share the bed every night and want room not to touch, or kids and pets regularly end up in it.
Stay Queen if the room is under about 3.3 m wide, or the cost of replacing all your King-size bedding, base and headboard matters more than the extra width.
King vs Super King
A Super King is 203 × 203 cm — 20 cm wider again, and square. It is a specialist size: the floor space required is significant, and bedding is harder to find and more expensive. For most people a King is the practical ceiling.
Will a King fit your room?
Allow around 60 cm of clear floor on any side you need to walk past, plus room for wardrobe and drawer doors to open fully.
- Walk both sides: about 3 m of width at an absolute minimum, 3.3 m to feel comfortable.
- Length: allow around 2.6 m from the head wall.
- Doors and hallways: check these before you order, not after. A King base or headboard is the piece that gets stuck, more often than the mattress.
Mark 183 × 203 cm on the floor with masking tape and leave it overnight. Walk the room in the dark on the way to the bathroom. It is a better test than any measurement.
Getting a King into the room
A King mattress that arrives compressed in a box is far easier to carry upstairs and around corners than an uncompressed one, because you are moving a box rather than steering a 183 cm slab through a doorway. It is still heavy, so plan on two people for the lift.
Bases are the part worth checking. Some King bases ship as two halves and some as a single piece, and that difference decides whether it makes it up a tight staircase. Check how a base ships before you buy it.
King bedding and bases
Buy bedding labelled King. Queen fitted sheets will not stretch to 183 cm, and Super King sheets will sit loose.
Check the fitted sheet's pocket depth against your mattress height, and add any topper you use.
Note that King pillowcases are a different thing from a King bed — a King pillow is a long pillow, and it is sold to suit any bed size. Two standard pillows or two King pillows both work on a King bed; it is a matter of preference, not fit.
Your base must be King. A King mattress on a Queen base overhangs by 15 cm on each side, which is uncomfortable to sit on and puts the mattress edges under strain.
Naptime King mattresses
We stock King across several models and firmness options. Because stock moves, the mattresses page shows what is genuinely available today rather than any list we could write here.
If you are choosing between firmness options, our guide to choosing mattress firmness goes through it by sleep position and body weight. You will also need a base in the same size — how to choose a bed base covers the differences.
Frequently asked questions
What are the dimensions of a King bed in Australia?
A King mattress is 183 cm wide and 203 cm long.
How much wider is a King than a Queen?
30 cm. A Queen is 153 cm wide and a King is 183 cm. They are the same length.
Is an Australian King the same as a US King?
They are close but not identical, and bedding sized for one can fit poorly on the other. Buy bedding to Australian sizing for an Australian mattress.
What size room do I need for a King bed?
Around 3.3 × 3.4 m lets you walk both sides comfortably. Under about 3 m of width, a King will feel tight.
Is a King bed the same as two Singles?
Almost. Two Singles side by side measure 184 cm wide against a King's 183 cm, but a Single is 188 cm long against a King's 203 cm, so the Singles are 15 cm shorter.
Do I need King pillows for a King bed?
No. King pillows are longer pillows, sold to suit any bed. Two standard pillows fit a King bed perfectly well.
Will a King mattress fit on a Queen base?
No. It will overhang about 15 cm on each side. Match the base size to the mattress.
Is a King worth it over a Queen?
If two adults share the bed nightly and the room is wide enough, most people who move up do not go back. If you are tall rather than cramped for width, a Queen already gives you the same 203 cm of length.
Browse all mattresses · See every Australian mattress size · Queen or King: which is better?
Naptime is an Australian-owned family business based in Capalaba, QLD (est. 2012), selling factory-direct so you get the mattress without the retail mark-up. Trusted by 100,000+ Australian customers, and rated 4.8 stars on Okendo. We take care of the rest.
