- 1). Open the cabinet door and measure the width of the face frame. The face frame is the wood that sits behind the cabinet doors. It is usually 1 1/2 to 2 inches wide. Place the end of the tape against the left side and measure across to the right. This is the rough opening width.
- 2). Read the tape measure closely. Make certain that you include the fractions of the inch measurement. A tape measure is broken down into 1/16th of an inch measurements between whole inches. Count the marks to determine the fraction of a inch. For example, if the tape reads 5 plus 5 small lines, the measurement is 5 5/16ths of a inch.
- 3). Measure the face frame opening from the bottom to the top. Read the tape measure closely. This measurement will give you the vertical rough opening.
- 4). Measure the width of the cabinet door. Place the tape on the far left side of the door and pull it straight across the door to the right side. Read the tape closely.
- 5). Subtract the measurement for the rough opening from the measurement for the door width. Divide the answer by two to get the door overlay. For example, for a rough opening of 20 inches and a door width of 21 inches: 21 minus 20 equals 1 inch; 1 inch divided by 2 equals 1/2 inch overlay.
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