Standard Door Size 101: Important Measurements All Homeowners Should Know
Purchase the proper size interior and entry doors to suit your home remodel or new construction—and learn which make the most reasonable DIY projects.
Q: We just purchased a home that was built in the 1960s and will be remodeling to bring it up to date. Our plans include adding some new doors, and we’re wondering what sizes will work best. Are there any standard door guidelines?
A: Congratulations on your home purchase! Not all older homes have similar size doors, because many houses were built before local building codes were established and doors were often crafted by hand. Today, doors come in standard sizes and are stocked at DIY stores and home improvement centers. In addition to stocking standard door sizes, many stores also keep a few alternate sizes on hand, which can be used in certain areas of the house.
There are standard door sizes and some alternates available.
Interior doors come in standard heights, widths, and thicknesses, as follows:
- Standard door height for interiors is 80 inches. This is the most common height for passage doors that lead from one room to another. An 80-inch door is called a 6/8 door (pronounced “six-eight”) because it’s 6’ 8” tall.
- In stock, you will also find a slightly shorter 78-inch door. Called a 6/6 door, it’s reserved for closet and utility doors.
- Standard door width for interiors is 32 inches. This is the minimum width required for a passage door.
- You may also find a few narrower doors in stock, including 30 inches, 28 inches, and 24 inches. Code allows these narrower widths as closet and utility doors.
- You may possibly find 36-inch-wide doors in stock. These wider options are compliant with the Americans with Disabilities Act (ADA) and are a popular choice for homes whose residents have mobility issues.
- Standard interior thickness is 1⅜ inches. This is the most common interior door thickness and sometimes the only one stocked at home improvement stores.
- Some stores may stock doors with alternate thicknesses of 1½ inches and 1¾ inches. These are slightly thicker than standard and are often insulated or made from hardwood.
- Standard interior door jamb thickness on pre-hung doors is 4-9/16 inches. The door jamb is the frame that installs in the wall and supports the door via hinges. This thickness is designed for installation in a standard two-by-four wall (constructed by studs that are actually 1½ inches by 3½ inches).
- An alternate jamb thickness is 6-9/16 inches. It’s designed to fit two-by-six walls (constructed by studs that actually measure 1⅕ inches by 5½ inches).
Measuring for a new door is a simple process.
Most of the time when you buy a door, you’ll want a pre-hung door, which means it comes with the frame (jamb) included. The other type of door, called a “slab door,” features only the door, no jamb.
Measuring for a Pre-Hung Door
- Open the door and measure from the inside of one jamb to the inside of the opposite jamb—this is the spot where the sides of the door would fit when closed. Write the number down.
- With the door still open, measure from the inside top of the jamb (where the door would fit when closed) to the floor. Subtract ¾ inch and write the number down. The ¾ inch subtraction is for flooring allowance.
- Measure the thickness of the door itself, and write the number down. Take all three numbers with you when you visit the home improvement center.
Measuring for a Slab Door
- When measuring to replace a slab door, measure the width, height, and thickness of the door itself—not the jamb.
Choose a pre-hung door with slightly smaller measurements.
This way, you or a professional carpenter (you’ll need basic carpentry skills to hang a door) can fit the new door frame within the rough opening for the old door. It’s common to have to add some shims for a tight fit. Avoid buying a pre-hung door with measurements slightly larger than your existing door if this is a DIY project. In order to fit the door jamb, a portion of the rough-in frame (in the wall) would have to be removed, and because that could alter the load-bearing structure of the wall, it’s a job for a pro.
Or, select a slab door with slightly larger measurements.
If you’re only replacing the door, not the jamb, if you buy a smaller door, you’ll end up with gaps between the door and the jamb. Instead, buy a slab door that’s slightly larger and then shave it down to the exact size of the existing door. As a DIY project, expect fitting a slab door to be time-consuming, as it requires precision to create the indentions needed to fit the hinges and install a new strike plate that perfectly matches the existing door. While it may seem simpler to install a slab door, it’s actually more complicated than installing a pre-hung door.
If you want more wall space, consider a narrower door.
Large doors can overwhelm small rooms, so if space is at a premium, a narrower door can provide a cleaner look and add wall space. This involves removing the old door and jamb and reconfiguring the rough-in frame in the wall so a new pre-hung door will fit the space. This project is well within the capabilities of a DIYer with basic carpentry knowledge.
Consider remodeling with wider doors if your home’s doors are too narrow.
It can be difficult (if not impossible) to move large furniture through small doorways, so widening them may be a must when remodeling an older home. You may find a few 36-inch doors in stock, but your best bet is to order custom doors from a home center. These doors should be installed by a knowledgeable pro because the rough-in opening in the wall will have to be enlarged.
You can also order a custom size pre-hung door.
If your measurements don’t closely match the standard size for doors available at the store, but you’re not prepared to enlarge or narrow the existing door frame, know that manufacturers will create pre-hung doors to your exact specifications. If you choose this route, your door will fit perfectly in its jamb, and open and close with ease. This allows you to remove the old door casing and trim, install the new door, and then reinstall the original casing and trim and either paint or stain the new door to match.
Entry doors are usually 36 inches wide.
While a door width of 36 inches is oversized for an interior door, it’s the standard size for front doors. The standard height remains the same, however, at 80 inches. Most entry doors are slightly thicker than interior doors as well, with a standard thickness is 1¾ inches. These slightly wider doors make it possible to move appliances and large furniture items into the home. Standard jamb thicknesses are similar to interior door jamb thicknesses, either 4-9/16 inches or 6-9/16 inches to fit two-by-four and two-by-six walls, respectively.