How to determine the correct size door to order
The first step in ordering is determining what size opening you have to work with. This door size chart will help determine the width and height of door units to order. Interior and exterior have similar but also different considerations so make sure to read this chart correctly.
The door slab widths and prehung unit widths are included for both interior and exterior doors. The heights for both interior and exterior doors are listed for the slabs widths only across the top and the finished prehung unit heights.Make sure you are looking at the measurement that applies to the correct unit you are looking to replace.
All exterior doors are 1 3/4 standard slab thickness and all interior door slabs are the standard 1 3/8″ thickness. The standard door frame width (thickness) is 4 9/16 for interior and exterior doors although the frames are different in composition. All our exterior doors are NO-ROT composite to withstand the exterior elements and are stronger. Exterior composite brickmold must be specified because there are variations. For interior doors they are hung on 4 9/16 primed flat jambs and can come with or without colonial primed trim.