How Thick Should a Mattress Be?
Quick answer: A standard mattress is 20–30 cm thick (8–12 inches). Most adults sleep best on a mattress around 25–30 cm. Side sleepers, couples and heavier sleepers often prefer 30–35 cm for extra cushioning, while kids, bunk beds and lightweight sleepers may only need 13–25 cm. The right mattress thickness depends on your sleep position, body weight, mattress material and bed base height.
When buying a mattress, most people compare size, firmness and material first. But mattress thickness also matters because it affects comfort, support, total bed height, sheet fit and how easy the bed is to get in and out of. This guide covers the standard mattress thickness in Australia in cm and inches, how thickness varies by sleep position and body weight, queen mattress thickness, and how to match the right thickness to your bed base.
If you're replacing your mattress, browse the Levede mattress collection to compare types, sizes and comfort options.
How thick is a mattress? Standard thickness in cm and inches
Most Australian mattresses are 20–30 cm thick (8–12 inches) . A few thinner options exist for kids and bunks (around 13–20 cm / 5–8 inches), and premium hybrid or pillow-top mattresses can reach 35 cm or more (14+ inches).
Mattress thickness chart: heights in CM and inches
| Mattress Type | Height (cm) | Height (inches) | Best For |
|---|---|---|---|
| Low profile mattress | 5–13 cm | 2–5 in | Toddlers, foldaway beds, some bunk beds |
| Slim mattress | 13–20 cm | 5–8 in | Kids, guest beds, lightweight sleepers |
| Standard mattress | 20–30 cm | 8–12 in | Most adults, everyday bedrooms, guest rooms |
| Thick mattress | 30–35 cm | 12–14 in | Side sleepers, couples, extra cushioning |
| Extra-thick mattress | 35 cm+ | 14 in+ | Plush bedroom setups, taller bed feel |
Mattress thickness in cm vs inches: 20 cm ≈ 8 inches, 25 cm ≈ 10 inches, 30 cm ≈ 12 inches, 35 cm ≈ 14 inches. A thick mattress isn't always better, a well-made 25 cm mattress can feel more supportive than a poorly built 35 cm one.
Is a 5, 6, 7, 8 or 10 inch mattress thick enough?
A common question among shoppers is whether a thin mattress will be supportive enough. As a quick guide:
- 5 inch (13 cm) mattress Thick enough for toddlers, bunks and very lightweight sleepers. Too thin for most adults.
- 6 inch (15 cm) mattress Acceptable for kids and lightweight adult guests on a short-term basis. Not recommended for daily use.
- 7 inch (18 cm) mattress The minimum for an adult on a slatted base; suits lightweight or budget setups.
- 8 inch (20 cm) mattress Generally thick enough for most lightweight to average-weight adults.
- 10 inch (25 cm) mattress Comfortable for most adults across sleep positions.
- 12 inch (30 cm) mattress A safe choice for couples, side sleepers and heavier adults.
If you're using a topper or mattress protector, add that thickness on top when planning sheet fit and bed height.
What is the standard mattress thickness?
The standard mattress thickness is 20–30 cm (8–12 inches). This range suits most adults because it allows enough room for comfort layers and a strong support core without making the bed too tall.
A standard-height mattress works well for everyday bedrooms, guest rooms, back sleepers, combination sleepers, and anyone wanting balanced comfort and support.
If you're unsure which feel suits you, read Levede's mattress firmness scale guide before choosing your mattress thickness. Thickness and firmness work together, but they aren't the same thing.
How thick is a queen mattress?
Most queen mattresses in Australia are 20–35 cm thick , with the typical queen mattress sitting at 25–30 cm . Thicker queen mattresses (30–35 cm) suit side sleepers, couples or anyone wanting extra cushioning.
If you're shopping for a queen size bed, compare your mattress thickness against your bed frame height. A thick queen mattress on a tall frame may make the bed too high to climb into; a thin mattress on a low platform frame may feel too close to the floor.
For queen-specific buying help, view Levede's queen mattress collection , the best queen mattress Australia guide , or the queen mattress size guide .
What makes up mattress thickness?
Mattress thickness isn't just about how tall the mattress looks it comes from the layers inside the mattress . These layers affect comfort, support and how long the mattress holds its shape.
Comfort layer
The top section you feel first when you lie down. It handles surface comfort, pressure relief, softness and initial body cushioning. Common comfort layer materials are memory foam, gel foam, quilted foam and latex.
A comfort layer that's too thin may feel firm or flat. One that's too thick and soft may sink too much, especially if the support base underneath is weak.
Transition layer
Some mattresses include a transition layer between the comfort layer and the support base. It softens the move from soft top foam to a firmer base, helping with gradual support, pressure balance and weight distribution. Common in hybrid and foam mattresses.
Support layer
The base of the mattress it gives your body deeper support and keeps the mattress in shape over time. Common support systems include high-density foam, pocket springs, Bonnell springs, latex cores and hybrid spring-and-foam builds.
The support layer should make up a large part of the total mattress height. A thick mattress with a weak support core may still sag.
How to Choose Mattress Thickness by Sleep Position
Your sleep position affects how much cushioning and support you need.
Side sleepers
A mattress around 30–35 cm suits side sleepers extra cushioning relieves pressure at the shoulders and hips. Look for a mattress that combines cushioning with stable support. Too firm creates pressure points; too soft lets the hips sink too far.
Back sleepers
A mattress around 25–30 cm thick balances comfort and support for back sleepers. The goal is to keep the lower back supported without excessive sink. A medium or medium-firm feel works for most back sleepers.
Stomach sleepers
A firmer, more supportive surface around 20–25 cm is usually enough provided the support core is strong. Too much softness lets the hips dip, which feels uncomfortable over time.
Combination sleepers
A mattress around 25–30 cm works well for sleepers who shift positions during the night. A responsive mattress makes turning easier than a very soft, slow-moving foam mattress.
If you're choosing a mattress because of back discomfort, Levede's guide to the best mattress for back pain compares support, firmness and comfort options.
How body weight affects mattress thickness
Body weight changes how a mattress feels the same mattress feels firmer to a lighter person and softer to a heavier person.
| Body weight | Recommended thickness |
|---|---|
| Under 60 kg | 20–25 cm adequate comfort and support |
| 60–100 kg | 25–30 cm balanced comfort layer + support base |
| Over 100 kg | 30–35 cm with strong support core reduces bottoming out |
Thickness alone isn't enough. Always check the material, firmness and support system before buying.
How your bed base impacts mattress thickness
Your mattress and bed base work together. A thick mattress on a tall base can make the bed hard to climb into. A thin mattress on a low frame can feel too close to the floor.
As a general guide, a comfortable total bed height is around 55–65 cm from the floor to the top of the mattress.
| Bed Base Type | Common Base Height | Suggested Mattress Thickness |
|---|---|---|
| Platform bed | 25–30 cm | 25–30 cm |
| Slatted bed base | 20–30 cm | 25–30 cm |
| Box spring or foundation | 35–40 cm | 20–25 cm |
| Adjustable frame | 20–30 cm | Usually under 30 cm |
| Storage bed frame | Varies | Check total height carefully |
How thick should a mattress be for a platform bed?
A platform bed sits lower than a box-spring base, so a slightly thicker mattress of 25–30 cm works best enough cushioning to bring the sleeping surface up to a comfortable height without making the bed feel too tall. Memory foam and hybrid mattresses sit naturally on platform beds, while pocket spring mattresses also work as long as the slats are spaced 7 cm or less apart.
Setting up a queen bedroom? Compare your mattress with a suitable queen bed frame . For storage, a queen bed frame with storage helps maximise space just make sure the combined bed and mattress height stays comfortable.
How mattress material affects ideal thickness
Different mattress materials need different thicknesses to perform well.
Memory foam mattresses
Memory foam mattresses work best between 25–35 cm. This gives space for a comfort layer and a firmer support base underneath. A thin memory foam mattress can feel firm and offer poor pressure relief; a thicker one feels more cushioned but still needs strong support beneath.
If you want extra comfort without replacing the full mattress, a mattress topper adds 5–7 cm of surface cushioning. A 5 cm cool-gel memory foam topper softens a firm mattress; a 7 cm topper gives a thicker comfort layer.
Pocket spring and hybrid mattresses
Pocket spring and hybrid mattresses are usually 25–35 cm thick. The spring layer needs depth to compress properly, while foam or pillow-top layers add cushioning. These mattresses give support, airflow and a more lifted feel good for people who run warm. A 25 cm pocket spring queen suits a balanced profile; a 30–32 cm spring queen suits a taller, more cushioned feel.
Firm and extra-firm mattresses
Firm mattresses don't need to be extremely thick to feel supportive construction matters more than height. Sleepers wanting a firmer feel are often better off with an extra-firm queen mattress than just choosing the thickest mattress they can find.
Why are mattresses so thick now?
Australian mattresses have become thicker over the past 20 years because modern designs use multiple specialised layers a comfort layer for pressure relief, often a transition layer for weight distribution, and a support core (pocket springs, high-density foam or hybrid). Each layer needs its own depth to perform, which pushes total thickness up. Premium materials like gel-infused memory foam, micro-pocket springs and natural latex also add height.
Thicker mattresses aren't automatically better but they generally allow more zoned support, better pressure relief and longer lifespans than the thin spring mattresses of decades past.
Thick mattresses: benefits and drawbacks
A thicker mattress feels more cushioned and premium, but isn't always the right choice.
Benefits of a thick mattress (30 cm+):
- More cushioning and pressure relief for side sleepers
- A taller bedroom look
- More room for comfort layers
- Better suitability for couples or heavier sleepers (when build quality is good)
Drawbacks of a thick mattress:
- May make the bed too high to climb into easily
- Needs deep-pocket fitted sheets
- Heavier to rotate or move
- Can feel too soft for some sleepers
- Costs more than a standard mattress
If your current mattress is supportive but too firm, a topper is often enough. If it's sagging or no longer supportive, replacing the mattress is the better fix.
What's the thickest mattress you can buy?
The thickest mattresses sold in Australia are typically 35–45 cm (14–18 inches) , with some luxury hotel-style and pillow-top models reaching 50 cm. These extra-thick mattresses stack a plush pillow top, multiple foam layers, a transition layer and a deep pocket spring core.
Going beyond 35 cm is usually a comfort preference rather than a support need a well-built 25–30 cm mattress with the right firmness and support layers will outperform a poorly built 40 cm mattress for most sleepers. Extra-thick mattresses also need deep-fitted sheets (40 cm wall or more) and a lower bed base to avoid making the bed too tall.
The thinnest mattress sold for adults is around 13 cm (5 inches), suitable only for occasional or guest use. For everyday adult sleep, the minimum is 18–20 cm.
Do you need special sheets for a thick mattress?
Yes you'll need deeper fitted sheets if your mattress is over 30 cm thick , especially if you also use a topper or protector. Before buying sheets, check:
- Mattress thickness
- Topper thickness (if used)
- Mattress protector thickness
- Sheet pocket depth (look for 35–40 cm wall depth for thick mattresses)
If you use a topper, your total sleeping surface may become much taller. A queen mattress protector or topper can improve comfort but may affect sheet fit.
What mattress thickness is right for you?
The best mattress thickness depends on your body, sleep style, bed base and comfort preference.
| You Are Looking For | Suggested Thickness |
|---|---|
| Kids' bed or bunk bed | 13–20 cm (5–8 in) |
| Lightweight adult sleeper | 20–25 cm (8–10 in) |
| Most adults | 25–30 cm (10–12 in) |
| Side sleepers | 30–35 cm (12–14 in) |
| Couples | 28–35 cm (11–14 in) |
| Heavier sleepers (100 kg+) | 30–35 cm (12–14 in) |
| Low bed setup | 25–35 cm (10–14 in) |
| Tall bed base / box spring | 20–25 cm (8–10 in) |
If you want a simple starting point, most adults can begin in the 25–30 cm range, then adjust based on sleep position, body weight and preferred firmness.
For broader buying guidance, read how to choose the right mattress in Australia or browse the full Levede mattress range .
Frequently asked questions about mattress thickness
How thick should a mattress be?
A standard mattress should be 20–30 cm thick (8–12 inches) for most adults. Side sleepers, couples and heavier adults often prefer 30–35 cm for extra cushioning. Kids, bunk beds and lightweight sleepers can use 13–25 cm. The right thickness depends on your sleep position, body weight, material and bed base.
How thick is a mattress on average?
An average mattress is 25–30 cm thick (10–12 inches) in Australia. Budget and slim mattresses are 13–20 cm, while premium hybrid and pillow-top mattresses can reach 35 cm or more.
How do I measure mattress thickness?
Measure from the top sleeping surface down to the bottom edge of the mattress. Do not include the bed base, topper or mattress protector in the actual mattress thickness though you should add them when calculating total bed height and sheet fit.
How thick is a queen mattress?
A queen mattress in Australia is 20–35 cm thick , with most standard queens at 25–30 cm. Premium queen hybrids and pillow tops can reach 35 cm or more for extra cushioning and durability.
What is the standard mattress thickness in cm?
The standard mattress thickness in Australia is 20–30 cm , with 25–30 cm being the most common range. This suits most adults across sleep styles and works well with standard bed bases.
Is a thicker mattress always better?
No. Comfort depends on materials, firmness and support layers not just height. A well-built 25 cm mattress can outperform a poorly built 35 cm mattress. Thicker mattresses give more cushioning, but also weigh more, cost more and may need deep-pocket sheets.
How thick should a mattress be for side sleepers?
Side sleepers typically need a mattress thickness of 30–35 cm with a soft-to-medium comfort layer. This gives the cushioning needed at the shoulders and hips to relieve pressure while keeping the spine aligned.
How thick should a mattress be for heavy sleepers?
Heavier sleepers (over 100 kg) usually prefer a mattress around 30–35 cm with a strong support core dense foam, robust pocket springs or a supportive hybrid. The support system matters as much as the height.
How thick should a mattress be for a platform bed?
For a platform bed, choose a mattress around 25–30 cm thick . Platform beds sit lower than box-spring bases, so a slightly thicker mattress lifts the sleeping surface to a comfortable 55–65 cm total bed height.
What's the thickest mattress you can buy?
The thickest mattresses sold in Australia are typically 35–45 cm (14–18 inches) , with some luxury models reaching 50 cm. These stack a plush pillow top, multiple foam layers and a deep pocket spring core. Beyond 35 cm is usually a comfort preference rather than a structural support need.