Inner Door Standard Size (Dimension Guide)

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Here's our standard interior door size guide that includes the most common China WDMA door dimensions for the bedroom, bathroom, and closets.

The height of the door is its most standard dimension. All interior doors to be used as hallways between rooms must be at least 80 inches high. (6'8) This allows adequate space for the vast majority of people to use the entrance without hitting their heads.

Closet and utility doors, which are not used to travel between rooms, can be shorter. 78 inches (6'6 ") is a very common height for closet doors.

What is the standard size of the inner door?

Standard widths for different types of interior doors can range from 24 to 36 inches. The most common width for interior doors is 32 inches. Therefore, the standard size of the interior door is 32 ″ wide by 80 ″ high. Most people can clear a door this size without brushing the sides of the frame. If you want your home to be accessible to wheelchair users, each door must be at least 36 ”wide.

Standard inner door thickness

The most common thickness for interior doors is 1⅜ ”. Other door thicknesses are available, such as 1½ ”, 1⅝” and 1¾ ”. Oversized or especially large doors (over 90 inches high or over 36 ”wide) are often thicker than standard-size doors 

The thickness of the door becomes important when you order hardware such as knobs and hinges. Fire doors are also thicker than normal interior doors.

How to measure a door

Doors are one of the finishing touches added to new construction, but you can't wait until the final stage of the project to think about them. The final size of the door is established during the framing process. Contractors erect posts to form an "unfinished opening" between rooms and make it strong enough to support a door and a door frame. 

The general rule of thumb for rough openings is: they should be two inches wider than the door that will eventually be installed. This leaves room for the door frame and leaves a small gap on either side of the door, allowing it to open and close.

When it comes to height, the rough opening should be at least two and a half inches taller than the door. If the floor is very thick, the opening may need to be even higher so that the door can swing freely. 

Once you have the rough opening, your next step is to add a door frame and hang a door or install a pre-hung door. Before taking the final step of ordering your doors, be sure to measure the actual rough opening size; do not take plan measurements for granted.

To calculate the proper size for a replacement door, professionals recommend that you measure the doorway (the opening where the door will hang) rather than the existing door. This is because the wood (in the door or door frame) could have warped or changed shape in response to the weather. You will also need to set the desired thickness of the replacement door.

Interior door sizes 

The International Residential Code provides uniform safety and accessibility standards for single or two-family homes and townhouses. This is what the home inspector will refer to when he comes to sign your new home, in addition to local codes. 

While there are strict requirements for the main entrance to a home, interior doors are not required or regulated. Where they exist, they simply need to be in good working order and installed according to the manufacturer's specifications.