Decide if you’re measuring for:

• A pre-hung door (comes with a frame)
• A slab door (just the door, no frame)

• Measure horizontally across the opening at three points: top, middle, and bottom.
• Record the smallest measurement to account for any irregularities.
• Standard door widths are typically 28, 30, 32, or 36 inches, but custom sizes may vary.

• Measure vertically from the top of the doorway to the floor at two or three points: left, center, and right.
• Record the smallest measurement.
• Standard door heights are usually 80 inches (6 feet 8 inches).

• For pre-hung doors, measure the thickness of the wall (jamb depth), including drywall and any trim. Common depths are 4 9/16″ or 6 9/16″.

• If you’re replacing a pre-hung door, measure the rough opening (the framed space where the door and frame will go). Add about 2 inches to the door’s width and height for the rough opening size.

• Check for floor clearance. Measure from the bottom of the door frame to the floor to ensure the door can open without obstruction (especially for carpeted areas).

• Determine the door swing (left-hand or right-hand) by standing with your back to the hinges. If the door swings to your left, it’s a left-hand door; if it swings to your right, it’s a right-hand door.

• Double-check your measurements to avoid costly mistakes.
• If you’re measuring for a storm or screen door, take the measurements of the outer frame.
• Bring your measurements to the store or manufacturer when purchasing your door.