The ceiling height on the interior of a habitable structure and the hallways is 7 feet. If a room has a sloped ceiling, at least 50% of the ceiling height must be 7 feet or greater. IRC 305.1.

The ceiling height is allowed to be 6 feet 8 inches in laundry rooms, bathrooms and toilet rooms. IRC 305.1. For sloped ceilings in a bathroom the height must be 6 feet 8 inches in the center working area in front of fixtures (sink) and 6 feet 8 inches above the shower. 305.1.2