Net internal area (NIA) is a method of measurement that measures the useable area within a building.

The NIA method of measurement is generally applied to:

• Offices
• Shops
• Other retail premises, such as banks, hairdressers, restaurants etc.

With the NIA method, we exclude some spaces from the measurements such as:

• Service accommodation like toilets and associated lobbies
• Cleaners′ cupboards
• Lift rooms, liftwells and stairwells
• Boiler rooms, tank rooms, fuel stores and some plant rooms.

For shops and retail premises, the NIA measurements are then divided into zones.

How we measure property is detailed in our measuring guide, which complies with the measuring code approved by the Royal Institution of Chartered Surveyors (RICS).