A full bathroom is a room equipped with a 1) toilet, 2) sink, and 3) shower or bathtub.
A half bathroom contains a toilet and sink but does not contain a bathtub or shower.
A half bath greater than 45 square feet in size is considered as having a "rough-in" for a full bath.
A half bath accessed from the interior with an exterior door leading to a shower is considered a full bath.
For more information, see Definition of a Bedroom, Detached Residential Accessory Structures, and Detached Residential Accessory Structures Summary Table