Clear Width & Clear Height: Essential Internal Cabinet Dimensions

June 18, 2026

Clear width and clear height refer to the exact, usable internal dimensions of a piece of furniture between the carcass side panels, or between the base and top panel. These dimensions are crucial for the correct selection and installation of internal pull-outs, drawer runners, and hinges, as they define the actual space available minus all fitted components.

What Are Clear Width and Clear Height Exactly?

In furniture construction, a strict distinction is made between external dimensions (carcass dimensions) and internal dimensions. The clear width (also referred to as clear internal width) is the horizontal distance between the left and right inside panels of the cabinet. The clear height describes the vertical distance between the bottom base and the top shelf or upper panel. In addition, there is the clear depth, measured from the carcass back panel to the front edge (excluding overlapping fronts).

Just like the clearance height of a tunnel, the same applies in cabinet making: the clear dimension defines the maximum available space. If a component protrudes into this space, the effectively usable dimension is reduced. This is particularly relevant when planning internal pull-outs behind hinged doors.

Significance for Hardware and Fittings

The correct clear dimension is the fundamental requirement for the proper function of mechanical furniture components. An error of just 1 mm can cause pull-outs to jam or hinges to bind.

Drawers and Pull-outs: For installing complete drawer systems, the clear width must match the manufacturer specifications precisely. The runner slides require a defined lateral installation space. The clear depth also determines the maximum nominal length of the drawer runners.
Hinges and Door Protrusion: When standard concealed cabinet hinges are opened, the open door often protrudes a few millimetres into the carcass. This protrusion reduces the usable clear width. If internal drawers are to be fitted, either spacer strips must be used or specialist wide-angle hinges such as 155-degree concealed hinges with zero protrusion must be installed.
Internal Storage Fittings: Rigid built-in units such as a plate rack insert for wall units or smart base unit storage in kitchens also require verification against clear dimensions so that wire racks and baskets can be mounted without tension.

Dimensions and Practical Calculation

The clear width is calculated by subtracting the material thicknesses from the external dimension. Common carcass materials such as chipboard or MDF usually have a thickness of 16 mm, 18 mm, or 19 mm.

Calculation Example: A cabinet has an external width of 600 mm and side panels with a thickness of 16 mm.

Calculation: 600 mm - (2 × 16 mm) = 568 mm
The clear width is exactly 568 mm.

When planning depth, the back panel must be taken into account. If it is grooved in (often recessed by 10 mm to 15 mm from the rear edge), the clear depth is reduced accordingly. A typical carcass with an external depth of 500 mm often provides a clear depth of only around 480 mm.

Application & Selection in Furniture Planning

Whether planning a bathroom unit with drawers or a large-scale wardrobe with drawers, clear dimensions dictate the choice of hardware. Especially when retrofitting wardrobe accessories such as pull-out trouser racks or wardrobe lifts, the exact internal dimension must be determined before purchase. Always measure at several points (top, middle, bottom), as carcasses can distort slightly on uneven floors.