Quick Definition
Overlay is the amount the cabinet door overlaps the cabinet opening or face frame.
Basic Formula
The simplest way to calculate overlay is to compare the door size to the cabinet opening. For a single door, subtract the opening width from the door width, then divide the difference by two.
Calculating Door Size from the Opening and Desired Overlay
Sometimes you know the opening size and the overlay you want, and you need to figure out the door size. In that case, you work the other direction.
Single Door Formula
Add the desired overlay to both sides of the opening.
Double Door Formula
Add the overlay on both outside edges, then divide the total width between the two doors.
How to Measure It
1. Measure the width of the cabinet opening or the inside width of the face frame.
2. Measure the actual width of the cabinet door.
3. Subtract the opening width from the door width.
4. Divide the difference by two to get the overlay on each side.
Worked Examples
Example 1: Single door on a face-frame cabinet
If the cabinet opening is 15 inches wide and the door is 16 1/4 inches wide, subtract the opening from the door width and divide by two. (16 1/4 - 15) / 2 = 5/8 inch overlay.
Example 2: Double doors meeting in the middle
If a pair of doors covers a 24-inch opening and each door is 12 5/16 inches wide, the extra width on each side translates to approximately 5/16 inch overlay per door.
Worked Door Size Examples
Single door example: 30" opening with 1/2" overlay
For a single door, add the overlay to both sides of the opening. 30 + 1/2 + 1/2 = 31 inches, so the door width would be 31 inches.
Double door example: 30" opening with 1/2" overlay
For double doors, add the total overlay first, then divide by two. (30 + 1/2 + 1/2) / 2 = 15 1/2 inches, so each door would be 15 1/2 inches wide before allowing for any desired center reveal.
If you plan to leave a center gap between double doors, subtract that total reveal from the combined width before dividing. For example, with a 1/8 inch total center reveal, you would subtract 1/8 inch and then divide the remainder between the two doors.
Why Overlay Matters
Hinge overlay affects hinge selection, boring pattern decisions, reveal consistency, and whether the finished door layout will look correct on the cabinet. If the overlay number is off, the hinge may not perform the way you expect.
A Practical Tip
If you are replacing an existing hinge, it can be helpful to close the door, mark the edge of the opening behind it with painter's tape, and then measure the overlap directly. That gives you a quick field check before ordering replacement hardware.