Calculating Door Overlay: How to Find the Right Concealed Hinge

Door overlay defines how far a furniture door rests on the cabinet carcass side when closed, directly determining the correct hinge mounting type for a concealed hinge.

For carpenters and installers, calculating this dimension accurately is the most crucial step before fitting hardware. If the overlay does not match the hinge cranking, the door will catch, gaps will become uneven, or the front cannot be adjusted at all. This technical guide explains how to calculate overlay, outlines the available mounting types, and helps you identify the correct hinge for your project.

Key Selection Criteria: Overlay and Mounting Types

Door overlay (also referred to as door reveal coverage) is the measurement in millimetres by which the closed furniture front covers the front edge of the carcass side. To select the correct cranking for the concealed hinge, the ratio of the door width to the carcass side must be clear. Three fundamental mounting types result from the desired overlay.

1. Full Overlay (Surface Mounted Door)

With full overlay, the door covers almost the entire carcass edge. Only a small side gap remains (usually 1.5 mm to 2 mm) so that the door does not catch against the neighbouring cabinet when opening. With a standard carcass side thickness of 19 mm, the door overlay here is typically 17 mm. Hinges for this application are straight-arm (uncranked). For this construction, choose concealed hinges full overlay.

2. Half Overlay / Twin Overlay (Dual Doors on Single Partition)

When two doors close onto a single central partition panel, this is referred to as a half overlay. Both doors share the front edge of the partition. With a 19 mm thick partition wall, the overlay per door is approximately 8 mm to 9 mm, minus the central gap. Hinges for this scenario feature a pronounced cranking. For this setup, you require concealed hinges half overlay.

3. Inset Mounting (Flush Door)

With inset mounting, the door does not rest on the carcass side, but sits flush within the carcass opening. The front finishes flush with the front edge of the carcass side. The overlay here is effectively negative. The hinge is deeply cranked to swing the door clear of the carcass opening during movement. Suitable hardware can be found in the categories concealed hinges inset and concealed hinges for inset doors.

Technical Details: Cup Size and Opening Angle

In addition to the mounting type, the drilled hole and the opening angle define the function of the door. The hinge acts like an articulated joint in the furniture carcass – it must deliver the exact lever mechanism and the correct clearance for the respective door weight.

• Hinge cup hole: The standard diameter for the hole in the furniture front is 35 mm. The drilling depth is usually 11.5 mm to 13 mm. Special dimensions (26 mm) exist for very narrow frame profiles, but installers generally rely on concealed hinges 35 mm.
• Standard opening angle: For standard cabinet doors in living or kitchen areas, an opening angle of 110° is the norm. It provides ample access to the interior. Concealed hinges / cabinet hinges 110 degrees cover the vast majority of standard applications.
• Special angles for specific geometries: When internal drawers are fitted, the door must swing completely clear of the internal opening width. Here, wide-angle hinges with 155° or 165° are essential. For corner cabinets with bi-fold doors, specialised angles such as 135° are used.

Decision Guide: Which Hinge for Which Application?

Hardware selection follows a clear technical logic. Use the following criteria to determine your requirements:

• If you are building a standalone cabinet with overlay doors, then choose a full overlay hinge with a 110° opening angle.
• If you are planning a cabinet run with shared central partitions supporting doors on both sides, then you require a half overlay hinge.
• If you are constructing a diagonal corner cabinet, then the geometry demands concealed hinges / cabinet hinges 135 degrees or concealed hinges / cabinet hinges 45 degrees, depending on the exact angle of the front relative to the carcass side.
• If doors are heavy or quiet closure is required, then choose soft close. Mechanically integrated soft-close dampers catch the door over the final centimetres of travel. Suitable models can be found under concealed hinges / cabinet hinges with soft close.

Installation Advice for Fitting

The correct operation of the hinge depends heavily on the precise positioning of the drillings.

1. Cup edge distance (drilling distance): This is the distance from the edge of the furniture door to the edge of the 35 mm cup hole. Typical values range between 3 mm and 6 mm. A larger drilling distance slightly increases the overlay, but requires precise alignment with the mounting plate.
2. Mounting plates: The cruciform mounting plate on the carcass controls the height and depth of the door. Most modern systems are based on the System 32 standard (32 mm hole line pitch, 37 mm distance from the front edge).
3. Adjusting door gaps: The adjustment screws on the hinge arm allow the door to be adjusted in three dimensions (height, depth, lateral overlay) down to the millimetre after installation.

FAQ: Frequently Asked Questions About Door Overlay and Concealed Hinges

How do I calculate the exact door overlay?

You calculate the door overlay by subtracting the gap width from the thickness of the carcass side. With a 19 mm carcass side and a desired side gap of 2 mm, the overlay is 17 mm. For central partition walls, divide the thickness of the partition by two and subtract half of the central gap.

What does the 35 mm measurement mean on a concealed hinge?

The 35 mm measurement refers to the diameter of the cylindrical cup hole routed into the back of the cabinet door front. The cup of the hinge is inserted into this hole and screwed into place.

Which opening angle do I need for internal drawers?

For cabinets with internal pull-out drawers, you need a hinge with zero protrusion. The door must open wide enough to leave the internal cabinet opening completely clear for the drawer runner. For this, choose concealed hinges / cabinet hinges 155 degrees or 165 degrees.

Can I mix soft-close and standard un-damped hinges?

Yes. On lightweight or medium-sized doors, one hinge with soft close per door is often sufficient, while the remaining hinges can be standard un-damped models. This reduces resistance when opening while still ensuring the door closes quietly and smoothly.

Which hinge do I need for a 90-degree blind corner or face frame?

For specialised constructions where the door sits at a right angle to the mounting surface (such as blind corner panels), concealed hinges / cabinet hinges 90 degrees are used.

Overview of Matching Products and Categories

To implement your calculated dimensions and suitable mounting type technically, navigate directly to the respective hardware range. The full selection of standard and specialised hinges for furniture making can be found in the main category concealed hinges / cabinet hinges.

For bespoke installations with narrower opening angles, such as angled cabinets beneath pitched roofs, check the technical specifications under concealed hinges / cabinet hinges 30 degrees. Always ensure when making your final selection that the mounting plates are fully compatible with your chosen hole pattern system.