What Is Standard Door Size?
In the us , two sorts of door sizes are mostly used for home interior and exterior doors. the quality door size for internal and external doors are as follows,
Interior Door Standard Size in inches = 80 Inch. (Height) x 36 Inch. (Width)

Exterior Door Standard Size in feet = 6 ft 8 In (Height) x 3 ft 6 In (Width)

Interior Door Standard Size in feet = 6 ft 8 In (Height) x 3 ft (Width)
Standard Size of Door Frame
The standard door size is 6 ft 8 during which doesn't include the dimensions of the door frame. The door frame size is usually wider than the door opening. The door frame post features a width between 2 to 4 inches.

The total width of door frame = Width of door frame + width of door + width of door frame