What is the maximum area of a bedroom?

All depends on the size of the bed and furnishings such as nightstands. I can recall bedrooms of starter homes from 9x10-9x12 with Masters a bit larger at 11x12-12x13. Larger masters can range from 14x15 up to 15x16 or even larger dependent on size of the home. The best way is to measure the size of the bed and furnishings and lay the dimensions out on a sheet of paper. Door swing, area to access closets and extra room at foot of bed and nightstands, should also be considered. You can purchase an architects template with various sizes and layouts of home furnishings.