Mattress thickness: How thick should a mattress be?

Mattresses vary in thickness, ranging from 6 to over 16 inches, depending on their construction and purpose. Thickness is an important factor to consider when choosing a new mattress because it may affect comfort, support and overall sleep quality.

There is a common misconception that deeper mattresses are more comfortable. While deeper mattresses often provide more cushioning, comfort depends more on the quality and quantity of fillings inside the mattress, as well as your personal preference.

The ideal mattress thickness depends on factors like body weight, sleeping position and preferred bed height. The average mattress thickness ranges from 10 to 14 inches, which is generally adequate for most adults.

However, in some situations, a thinner mattress may be more practical, such as when choosing a mattress for a bunk bed or one that needs to bend or fold to fit inside a frame or under the bed.

Different mattress thicknesses

Mattresses come in various thicknesses to suit different needs and preferences, from thin mattresses for children to thick, luxurious options for adults.

Thin mattresses

Thin mattresses are typically less than 8 inches deep and are usually made from foam or springs. They are often suitable for children’s beds, sofa beds, futons, or folding beds. These mattresses tend to feel firmer and may lack sufficient cushioning, making them less suitable for regular adult use.

Standard mattresses

Standard mattresses are usually 8 to 12 inches deep and have one or more comfort and support layers. They are suitable for most adults for regular use, providing adequate cushioning and pressure relief. Standard bedding should also fit mattresses within this depth range.

Deep mattresses

Deeper mattresses are typically 12 inches or thicker and are made with plush comfort layers. They are ideal for side sleepers as they provide extra cushioning for the shoulders and hips. However, deeper mattresses tend to be more expensive, and standard fitted sheets may not fit properly, so you may need extra-deep or custom-made bed sheets. 

What determines the thickness of a mattress?

The thickness of a mattress depends on its construction, the number of layers, and the depth of those layers.

The layer combination

Most mattresses are constructed with different layers for comfort and support. These layers are made from various materials and vary in thickness. The combination of these layers gives the mattress its unique feel.

Comfort layers

The comfort layers, located near the surface of a mattress, are designed to cushion the body and relieve pressure. Mattresses can have one or more comfort layers; some may even include an additional layer of micro or mini springs for extra comfort.

Comfort layers are chosen for their resiliency, durability, and breathability. These qualities affect how a mattress feels and performs. Cheaper mattresses typically contain synthetic materials, such as polyester, which often come in compact pads. In contrast, higher-quality mattresses typically contain large amounts of loose natural materials like wool, cashmere, and horsehair, providing a more luxurious feel.

Support layers

The support layer, usually made of foam or springs, is typically thicker than the comfort layers and ranges from 6 to 10 inches deep. It is typically made from durable materials which determine how far the body sinks into the mattress.

When springs are used in the support layer, their height can vary based on the number of turns in each spring. Generally, the more turns a spring has, the more responsive it is to weight.

Mattresses with more than 2,000 springs typically have multiple layers of springs stacked on top of one another, making the mattress deeper but more supportive.

Transition layers

Some mattresses have a transition layer between the support and comfort layers. The transition layer is typically made of sturdy materials and is usually around 1 to 3 inches deep.

Mattress types

Some types of mattresses tend to be thicker than others. For example, pillow-top and hybrid mattresses are usually thicker than traditional sprung or foam mattresses.

Pillow-top mattresses

Pillow-top mattresses have an extra layer sewn or stitched into the top of the mattress and are ideal for those who prefer a plusher feel. They typically range from 12 to 16 inches deep, depending on their construction and materials.

Hybrid mattresses

Hybrid mattresses typically combine springs with foam. They offer the perfect compromise for many sleepers by providing the support of springs and the comfort and cushioning of foam layers.

Hybrid mattresses tend to be deeper than ordinary mattresses to accommodate the thicker foam layers and spring system.

The manufacturing process

During manufacturing, the mattress upholstery is often compressed, reducing the mattress’s overall thickness. As a result, the mattress’s actual depth may not always reflect its quality. For example, pocket spring mattresses with high-quality fillings can appear relatively shallow, typically between 8 and 10 inches deep after compression.

Most mattresses are either quilted or tufted. Quilting involves stitching the cover to the surface fillings to create a smoother, flatter sleeping surface. Some mattresses may be deep quilted for extra cushioning, which may add a couple of inches to the mattress’s overall depth.

In contrast, tufting is often found in higher-quality mattresses. This technique secures the fillings by passing tapes or straps through the mattress, creating a deeper, more contoured surface.

Considerations for mattress thickness

A deeper mattress isn’t always better. The ideal thickness depends on factors like body weight, sleeping position, bed height, and compatibility with your bed base.

Body weight

Body weight is an important factor to consider when choosing mattress thickness. Heavier individuals tend to sink deeper into the mattress and often require a thicker mattress for adequate support. They may feel like they ‘bottom out’ on a thinner mattress.

In contrast, a lighter person, such as someone weighing under 11 stone, may find a thinner mattress adequate, as they apply less pressure on it.

Sleeping position

Your preferred sleeping position can influence the ideal mattress thickness. Side sleepers typically prefer a deeper mattress with plush comfort layers that cushion the shoulders and hips. In contrast, back and stomach sleepers generally require a firmer mattress to keep the body aligned and correctly supported. An overly thick mattress, however, may be too soft and cause misalignment.

Bed height

When choosing a new mattress, consider how its thickness impacts the bed’s height and how this affects getting in and out of bed. Bed height is particularly important for older adults or those with mobility issues. A deeper mattress may make it harder to climb into bed. In contrast, a thinner mattress lowers the bed height, making getting in and out of it more challenging.

Measure the mattress’s height carefully, especially if the bed is under a window or in a room with low ceilings. A deeper mattress may make the bed too tall for the window or reduce head clearance under the ceiling.

Also, consider the room’s aesthetics. A thicker mattress can make the bed look out of proportion with the room, potentially hiding the headboard or making the bed too tall for the other bedroom furniture.

Compatibility with bed base

In some cases, a deeper mattress may not be compatible with your bed base, making a thinner mattress a more suitable option.

Sofa beds

Sofa beds typically require a thinner mattress that can fold easily and fit inside the sofa when not in use. Thicker mattresses are often less flexible and may be too deep to sit inside the frame.

Adjustable beds

Adjustable beds require a mattress that can bend and conform to the base during operation. Deeper mattresses are often less flexible, making them unsuitable for adjustable beds.

Ottoman beds

Since ottoman beds have a lifting mechanism, the weight and thickness of the mattress are important factors to consider. Heavier or thicker mattresses may prevent the mechanism from operating smoothly.

Trundle beds

Trundle beds typically come with thinner mattresses to ensure they fit underneath the main bed and can be pulled out easily.   

Bunk beds

Bunk beds typically have a maximum mattress thickness, usually no more than 6 inches, to ensure the mattress sits below the safety rail. The maximum mattress height for a bunk bed is usually provided on a label on the bed or in the manufacturer’s instructions.

Low headboard

If your bed has a low headboard, a deeper mattress may hide most of it, affecting the overall aesthetics.

When purchasing a mattress separately, ensure it is compatible with your bed. Most mattresses aren’t designed to bend or fold, so if you’re using an adjustable or sofa bed, check with the manufacturer that the mattress is suitable.

Handling

Thicker mattresses are often heavy, less flexible, and difficult to move, which can cause delivery issues, especially in homes with access restrictions like low ceilings or narrow staircases.

Most mattresses also require regular turning to prevent uneven wear. Turning a thicker mattress may require more effort, so a thinner or non-turn mattress may be more suitable.

Bedding

Standard bedding is generally designed to fit mattresses up to 12 inches deep. Extra deep or custom-made bedding may be necessary for thicker mattresses. To ensure a good fit, measure the depth of your mattress before purchasing new bedding.

How to measure the depth of a mattress

Measuring your mattress’s depth will help you determine the appropriate bed height and ensure your bedding fits perfectly.

To measure the depth of your mattress, remove all bedding and use a tape measure or ruler to measure from the top to the bottom of the mattress. Avoid measuring from the seams, as this may not account for the extra loft on the surface and may give you an inaccurate measurement.

Write down or save the measurements on your phone so they are readily available when needed.

Final thoughts

Choosing the right mattress thickness is essential for quality sleep. A mattress that is too thin may be uncomfortable and lack proper support. On the other hand, a mattress that is too thick can make getting in and out of bed challenging and may be impractical for bedding or certain types of beds. The ideal mattress thickness is different for each person, so take your time to consider which works best for you. 

Finally, what matters most is what’s inside the mattress and how it is constructed. Check the mattress’s specifications to ensure you are satisfied with the material quality and quantity. Well-made mattresses with quality materials tend to be more comfortable, supportive, and durable.