What is the difference between a built in garage and attached garage?

An attached garage is attached to a structure (such as home) by a common wall or shared wall with another attached structure such as a covered porch, deck or breezeway. A built-in garage is contained within the structures footprint, and typically has living area over it that is accessible from within the main structure. where an attached garage has no living area over it. If an attached garage has area over it that is used for an office, living, storage, etc., it is not accessible from within the main structure or home. If it is, it's a built-in garage.