Q: What is the standard width and height for an interior door?
A: The standard interior door is 32 inches wide by 80 inches tall, with a thickness of 1⅜ inches. Common widths range from 24 to 36 inches, and heights are typically 80 inches, though 84-inch and 96-inch options exist.
Q: How do I measure an existing door to determine its size?
A: Measure the door slab itself—not the trim—at the top, middle, and bottom for width, and on both sides for height. Use the narrowest width and shortest height. Also measure the door edge thickness and note the swing direction.
Q: What is the difference between door slab size and actual door size?
A: The door slab size is the dimension of the door panel itself. The actual (or rough opening) size includes the frame or jamb, making it larger. For a 32-inch slab, the rough opening is typically about 34 inches wide. Prehung unit overall widths are larger than the slab because they include both sides of the jamb.
