According to the National Association of Home Builders, the average size of a master bedroom for a typical new family home is 309 square feet. The master bedroom is usually the largest bedroom in the home and typically comprises roughly 12% of the home's total area.
In smaller homes, the master bedroom is often one of the largest rooms in the whole house. Because master bedrooms are designed for couples, they require enough space to accommodate the needs of two people, and must be roomy enough to hold a queen- or king-sized bed. They also must have more closet space than other bedrooms.