Not All Doors Are the Same Size — And Why That Matters
When we hear the word door, most of us picture something simple: a flat slab of wood, maybe painted white, that swings open and closed. But once you step into the world of construction, architecture, or even DIY home improvement, you’ll quickly discover a surprising truth — not all doors are the same size.
In fact, door sizes vary more than you might expect, and that variation plays a big role in design, functionality, and accessibility. Whether you're renovating a home, buying furniture, or just trying to move a couch into the basement, knowing the basics of door dimensions can save you frustration (and bruised knuckles).
Why Are Door Sizes Different?
There are a few key reasons doors come in different sizes:
1. Purpose of the Door
Not every door serves the same function. Interior doors, like bedroom or closet doors, are often smaller than exterior doors, which need to accommodate large items like furniture — and people wearing winter coats.
Interior doors typically range from 24 to 36 inches wide, with 30 inches being common in older homes.
Exterior doors are usually 36 inches wide to meet modern building codes and allow for accessibility.
Closet or utility doors can be even narrower — sometimes just 18 inches wide.
2. Building Codes and Accessibility
Accessibility standards such as those outlined by the Americans with Disabilities Act (ADA) require doors to have a minimum clear opening of 32 inches to allow wheelchairs through. That affects how wide the actual door needs to be — and also the hardware and swing clearance.
3. Architectural Style and Era
Older homes often have non-standard door sizes. A charming 1920s bungalow might have 28-inch-wide doors throughout, while a modern custom home may feature dramatic 8-foot-tall entry doors.
Real-World Implications
Here are a few scenarios where door size really matters:
Buying New Furniture: That sleek sectional might look perfect online — until you can’t get it through the front door.
Renovating or Remodeling: Replacing an old door with a new one? You’ll need to measure both the door slab and the rough opening.
Installing Appliances: Many modern refrigerators or washers are too wide for older doorways. Always check dimensions before delivery day.
Building for Accessibility: If you’re designing for aging-in-place or accommodating a family member with mobility challenges, wider doors are a must.
How to Measure a Door (Properly)
If you're planning any kind of project that involves doors, here's how to get accurate measurements:
Width: Measure the door slab, not including trim.
Height: Measure from the bottom of the door to the top.
Thickness: Most doors are 1 3/8 inches thick for interiors, 1 3/4 inches for exteriors.
Rough Opening: Measure the frame inside the wall — this determines the size of the door unit you can install.
That seemingly simple doorway in your home is more complex than it looks. From building codes to furniture logistics to design choices, door dimensions affect far more than we give them credit for.
So next time someone tells you "it’s just a door," you’ll know better. Because in truth, not all doors are the same — and they were never meant to be.
