Requirements to become an interior designer vary by state, as some states require either certification, registration or a license to be an interior designer. These requirements generally have certain educational, testing or work experience requirements. However, one must always pass the National Council for Interior Design Qualification exam.
Many interior designers choose to specialize in subfields such as kitchen and bath design, hospital room design, restaurant design and others. Certification in each subfield can be conferred by various professional organizations; for example, one can be certified as a specialist in kitchen and bath design in the National Kitchen and Bath Association.