Standard Dimensions of Doorways and Doors

Standard Size

• Door sizes don't vary greatly between the United States and Europe, though in Europe, standard door and doorway dimensions are expressed in meters and millimeters rather than feet and inches. Ancient castles and other types of historic dwellings are liable to have doorways much smaller than those found in modern construction on either side of the Atlantic.

Shimming

• Another factor to consider when planning door and doorway sizes is to leave a bit of room over the top of the frame and on each side when you cut the initial opening. It's rare that a frame and door fit perfectly in the hole on the first try, and this leaves you some wiggle room within which to insert shims -- small pieces of wood -- to insure the doorway is perfectly aligned. A tiny variation can cause the door to fit poorly, resulting in a variety of problems.

Bathroom and Bedroom

• Bathroom and bedroom doors are often somewhat smaller than the standard size, often measuring as much as a couple of inches shorter and a up to a foot narrower than standard. Regardless of which type and size of door you want to use, it's best to measure obsessively to make sure you have enough space on the wall to accommodate your plans. Skilled builders will be able to integrate nonstandard door sizes into the design, if that's your preference.

Considerations

• Alternate door styles like sliding glass patio doors and double-paneled French doors vary from the standard considerably, perhaps as much as doubling the standard dimensions. As with standard sizes, utmost care should be taken to insure there is enough room to make the installation, including a shim allowance 1/2 inch wide on each side and 5/8 inches above, according to Ask The Builder columnist Tim Carter.