Mattress thickness, or "profile height", is one of the first things shoppers notice and one of the most misunderstood. A thicker mattress looks more luxurious, so it is easy to assume thicker always means better. It does not.
This guide explains what mattress thickness actually tells you, what profile suits your body and sleep style, and why the total height of your bed matters more than the mattress alone.
Typical Mattress Thickness in Australia
Most modern mattresses fall somewhere between 20 cm and 35 cm thick, with many quality hybrids landing around 25 cm to 30 cm.
That range is a guide, not a rule. What matters is what is inside the profile, not the number on the spec sheet.
What's Inside the Profile
A mattress profile is made up of two parts working together.
- The support core, usually a pocket-spring unit or a firm foam base, which provides the structural support that keeps your spine aligned.
- The comfort layers on top, which provide cushioning and pressure relief.
A well-built 26 cm mattress with a quality support core and dense comfort foam will outperform a 32 cm mattress padded out with cheap, low-density foam. Thickness only matters in the context of what fills it.
Does a Thicker Mattress Mean Better Quality?
No. Thickness is a design choice, not a quality measure. Manufacturers can add height with extra foam that does little for support and may even trap heat or sag early.
The specs that actually predict quality are foam density and the type of support core. Our guide on memory foam density explains the one number worth checking before you buy.
Thickness by Sleeper
Use these as starting points, then confirm with how the mattress actually feels.
| Sleeper | Suggested profile | Why |
|---|---|---|
| Lighter adults and children | Around 20 to 25 cm | Less depth needed to get proper support |
| Average-weight adults | Around 25 to 30 cm | Balanced comfort and support |
| Heavier sleepers (over 120 kg) | Around 28 cm or more | More support core and durable comfort layers |
| Side sleepers | Towards the thicker end | More cushioning for shoulders and hips |
If you carry more weight, our guide on choosing support for your body weight and sleep style goes deeper.
Thickness Plus Bed Base Equals Total Bed Height
Here is the part people forget. Your comfort getting in and out of bed depends on the total height of mattress plus base, not the mattress alone.
A tall mattress on a tall bed frame can leave the surface too high to sit on comfortably, which matters for older sleepers, anyone with mobility issues, or shorter people. A good target for the top of the mattress is roughly knee height when you sit on the edge, so your feet rest flat on the floor.
Tip: before buying, add your mattress thickness to your bed base height. If the total feels too tall, choose a slimmer base rather than a thinner mattress, so you do not sacrifice support.
A Note on Fitted Sheets
Thicker mattresses need deep-fitted sheets. If your mattress is on the taller side, check that your sheets have enough depth to tuck under properly. This is a minor point, but it saves the frustration of sheets popping off in the night.
Frequently Asked Questions
Is a thicker mattress better for back pain?
Not necessarily. Back support comes from the right balance of a firm support core and pressure-relieving comfort layers, not from sheer thickness. A thinner mattress with the right firmness can support your back better than a thick one with a soft, sagging core. See our guide on choosing a mattress for back pain.
What is the standard mattress thickness in Australia?
Most quality mattresses sit between 25 cm and 30 cm. Anything much thinner may lack support layers, and very thick mattresses are often padded with extra foam that adds height more than performance.
Can a mattress be too thick?
Yes, in a practical sense. A very thick mattress on a tall base can make the bed awkward to get in and out of, and may need specialty deep sheets. It does not make the mattress better, just taller.
Does thickness affect firmness?
Not directly. Firmness comes from the materials and how they are layered. Two mattresses of the same thickness can feel completely different depending on the foams and springs inside.
