If you are adding a new doorway, building a new home, or replacing doorways, you will need to keep some basic numbers in mind when framing as there are standards for how wide a door frame can be.
While this may bum you out if you’re an eccentric architect or decorator, there is some wiggle room. It’s also important to note that there are actually two sets of standards: one for exterior doors on a home, and one for interior door sizes.
NOTE: Building codes differ between areas, so while the following numbers represent what is accepted as the standard for a large majority of people, it may differ for you. Be sure to check your individual code before you begin your build.
International Residential Code requires the main entry door of a house to be at least 36 inches wide and 80 inches high. While they don’t employ any codes on any other exterior door other than this main entry door, keeping the 36 inch number in mind may be helpful.
For example, despite it being possible to acquire and install a secondary exterior door of any width, the lumber yards that make the doors stock the most common sizes with the greatest availability and pricing. The most common exterior door widths are 28, 30, and 32 inches
Generally speaking, all interior doors have a standard width of 34 inches. This is for bedroom, bathroom, and hallway doors.
A good way to visualize these measurements is to think of two people being able to walk through the door at the same time. You should be able to move chairs, sofas, mattresses, and appliances through these door frames without difficulty. These dimensions are observed for both homes and offices.
The exceptions to this rule is often seen with half bath doorways. A half bath door usually measures between 25 and 30 inches wide depending on the style of door.
Another exception to the width rule is for handicapped accessible doorways. In most areas, the building code for handicapped accessible doorways is 32 inches wide. In some areas, such as outside doorways, it is 34 inches wide.
Always check with your local code enforcement officials for standard door widths in your areas. Your local home improvement store will also be able to help you with these measurements, as they vary in different areas.
Sizing Door Openings
Another thing to consider isn’t just the door frame, but the size of the door opening. These are important because they must also account for door jamb material to be within their widths.
It’s common practice for framers to typically add about 2 inches of buffer to the standard, so door openings often vary between 36 inches and 38 inches for width standards.