Mattress Thickness vs Cabinet Depth: Murphy Bed Fit

How Cabinet Depth and Mattress Thickness Work Together

A Murphy bed's cabinet depth is the distance from the front face of the closed cabinet to the back panel against the wall. On a listing, that number appears in the dimensions, usually as the third measurement after height and width. The mattress thickness is the height of the mattress from its bottom to its top. In a closed Murphy bed, the mattress sits inside the cabinet, so the cabinet depth has to be large enough for the mattress plus everything that moves with it. For more on the cabinet dimension itself, see the guide to cabinet depth.

The maker's stated mattress height is the number to trust. Wilding Wallbeds, for example, publishes the mattress type that belongs with each of its cabinet beds, and its desk bed page pairs a specific 10-inch mattress with a stated cabinet depth. When a seller lists dimensions without a mattress height, that missing detail is a question to ask before you buy.

What fills the cabinet when the bed is closed:

the mattress itself

the platform or slats that support it

the lifting mechanism

the legs or hinges that fold with it

• the mattress itself
• the platform or slats that support it
• the lifting mechanism
• the legs or hinges that fold with it

Cabinet Beds Use a Tri-Fold Mattress

A cabinet bed, sometimes called a Murphy chest, folds the mattress into a freestanding cabinet. The mattress creases in two places, so the three sections stack inside the cabinet when the bed is up. Because the mattress folds, its thickness sets the height of the folded stack, and the cabinet depth must match that stack.

Wilding Wallbeds states that its Murphy Cabinet Beds include a 6-inch tri-fold mattress and that most of its cabinets are 24 to 27 inches deep when closed, depending on the model. Night and Day Furniture lists tri-fold gel memory foam and tri-fold gel pocket coil mattresses in its cabinet collection, which shows that the mattress is part of the cabinet bed design rather than an optional extra.

If you replace a cabinet bed mattress later, look for the same tri-fold construction and a similar thickness. A one-piece mattress cannot fold into a cabinet bed, and a thicker tri-fold may not let the cabinet close.

Wall Beds Stand the Mattress on End

A wall bed opens differently. The mattress rotates up around a hinge, so it stands on its side inside the cabinet. In a vertical-fold wall bed, the head end points up and the cabinet depth has to fit the mattress thickness plus the platform and the mechanism. That is why a wall bed can take a taller mattress than a cabinet bed.

Wilding's Murphy Desk Bed shows the relationship. The maker lists a cabinet depth of 21 inches and describes the open bed with a 10-inch mattress sitting about 32 inches from the floor. The same design keeps 17 inches of clearance for items left on the desk, which is possible because the desk rides level as the bed moves. The cabinet depth and the mattress height are published together so the buyer can see the fit.

Mattress Height Options for Murphy Beds

Murphy bed mattresses are built differently from regular mattresses. Wilding describes its foam-core mattresses as engineered to stand on-end without slumping or sagging over time, and it sells them in heights from 8 to 12 inches across its lineup. These are the mattresses designed for wall beds, where the mattress rises upright each time the bed closes. The guide to mattress thickness covers this in more detail.

A taller mattress changes the height of the sleeping surface when the bed is open. The desk bed example places the top of a 10-inch mattress at about 32 inches from the floor, so an 8-inch mattress sits lower and a 12-inch mattress sits higher. For a guest who has trouble climbing into a high bed, the thinner end of the range may suit better.

Reading a Listing for Thickness and Depth

Look for two numbers in any Murphy bed listing: the mattress height the maker specifies or includes, and the cabinet depth. A cabinet bed will state a tri-fold size, such as "6-inch tri-fold mattress." A wall bed will state a recommended height, such as "10-inch mattress." If the listing omits both, treat it as a signal to contact the seller.

Check whether the mattress is included. Cabinet beds often include it, as Wilding's do. Wall beds usually do not. When the mattress is separate, the maker's recommended thickness becomes your buying target, and the same rule applies to DIY kits, where the instruction manual states the mattress it is built for. The mattress compatibility guide explains how to match a replacement mattress.

A listing should state:

Matching the Fit to Your Room

The room decides the bed type, and the bed type decides the mattress range. A guest room that doubles as a home office suits a wall bed with a desk, where the maker publishes the cabinet depth alongside the desktop depth. A studio or rental often suits a freestanding cabinet bed that includes the tri-fold mattress and needs no wall mounting.

For nightly use, budget for a taller foam mattress designed for Murphy beds. For occasional guests, the included tri-fold in a cabinet bed is the simpler setup. In every case, follow the maker's stated mattress height so the bed closes fully and the mechanism works as intended.

What to pick for your situation

Questions

Does a thicker mattress always need a deeper cabinet?

In a vertical-fold wall bed, yes, because the mattress stands on end and the cabinet depth must fit its thickness plus the platform and mechanism. In a cabinet bed, the mattress folds, so the depth relates to the folded stack. Always follow the maker's stated height.

Can I put a regular mattress in a cabinet bed?

No. Cabinet beds take tri-fold mattresses that fold in two places. A regular one-piece mattress cannot fold into the cabinet. Use the included tri-fold or a replacement with the same construction and similar thickness.

What happens if the mattress is too thick for the cabinet?

The bed may not close fully, and the mechanism may bind. Check the maker's stated mattress height before buying, and ask the seller if the listing does not state it.

Do wall beds and cabinet beds have the same mattress requirements?

No. Wall beds stand the mattress upright, so they can take taller foam mattresses. Cabinet beds fold the mattress, so they use a tri-fold. Wilding's cabinet beds use a 6-inch tri-fold, while its wall bed mattresses range from 8 to 12 inches.

Is a mattress included with a Murphy bed?

Often, for cabinet beds. Wilding's cabinet beds include a 6-inch tri-fold mattress. Wall beds usually do not include one, so you buy the mattress separately at the maker's recommended thickness.