Approximately 80% of Singaporeans are living in public housing. These apartments are mostly owned by the occupants and are located in housing estates, which are self-contained towns with amenities such as clinics, shops, schools, supermarkets, food centres, sports and recreational facilities and etc. They are known as HDB flats because they are built and maintained by the Housing and Development Board (HDB). For the classification of HDB flats, the living room is counted as one room.

2 room HDB Flat. Has 1 bedroom with a built-in area of about 41-45 sq m or 441-485 sq ft.
3 room HDB Flat. Has 2 bedrooms with a built-in area of about 54-82 sq m or 581-882 sq ft.
4 room HDB Flat. Has 3 bedrooms with a built-in area of about 73-105 sq m or 785-1130 sq ft.
5 room HDB Flat. Has 3 bedrooms with a built-in area of about 110-135 sq m or 1,184-1,453 sq ft.
Executive Apartment. Has 3 bedrooms with built-in area of about 150 sq m or 1,615 sq ft.
Executive Mansionette. Same as Executive apartment, except it has two levels.
6 room HDB Flat. Jumbo flat joint by two 3 room flats.

Singapore is a multi-races country. Therefore, there is an Ethnic Integration Policy for HDB flats. Under this policy, there is a prescribed limit on the proportion of a particular ethnic group allow to stay on each flat. The reason behind is to let Singaporean to mix and stay harmony together.