Door Anatomy

Doors are made up of several components that many people are not aware of. Learn more about the pieces that work together to make a door. (For general purposes, a panel door is explained.)



Vertical boards that run the full height of a door and compose its right and left edges. The hinges are mounted to the fixed side (known as the “hanging stile”), and the handle, lock, bolt, and/or latch are mounted on the swinging side (known as the “latch stile”).


Horizontal boards at the top, bottom, and optionally in the middle of a door that join the two stiles and split the door into two or more rows of panels. The “top rail” and “bottom rail” are named for their positions.


Large, wider boards used to fill the space between the stiles, rails, and mullions. The panels typically fit into grooves in the other pieces and help to keep the door rigid. Panels may be flat or raised designs.

Anatomy of a Door

Anatomy of a panel door



The part of the door unit that is attached to the floor under the door.


The vertical boards that form the sides of a door frame, where the hinges are mounted, and where the latch connects with the strike.

Door Stop

A thin piece of wood attached inside the frame to stop a door from swinging through the jamb.


The decorative molding that outlines a door frame.



The distance from the edge of the door to the center of the hole drilled for the knob, lever or deadbolt.  It is necessary to specify 2-3/8” or 2-3/4”.

Cross Bore

The large 2-1/8” diameter hole where the actual lockset or deadbolt is mounted.

Latch Bore

The small, 1” diameter hole on the edge of the door.


Backset measurement

Center to Center

The distance between the center of the top cross bore (deadbolt) and the center of the bottom cross bore (latch).

This measurement is needed when shopping for exterior door handlesets.  Most doors are 5 ½”.

Center to center diagram

Center to Center measurement

Door Thickness

Distance from the inside edge to the outside edge of a door. The industry standard for modern (post-1950) front doors is 1-3/4” thick. Many interior doors measure 1-3/8” thick. If your door is thicker than 1-3/4”, choose a thick door kit from Grandeur Hardware.

Door Thickness measurement