"Interior Decorators" like to call themselves "interior designers", but true "interior designers" do not like to be called "interior decorators". Technically,

"Interior Decorators" like to call themselves "interior designers", but true "interior designers" do not like to be called "interior decorators". Technically, "interior design" is a subset/related to architecture. "Interior decorators" don't know much about building materials, and don't use Pantone colors. Interior designers know things like how wide walkways are supposed to be, how many square feet you need per-person (and how to arrange common areas to meet this legal (firecode) requirement), knows where exit signs should go, etc. There is also a significant amount of project management work that Interior designers do, in terms of managing the build out schedules and doing a lot of the technical grunt work in a build out.