International Standard Calculation Rules for Area

Learn the rules used by the International Standard to calculate area.

Unfinished Area (UA)

The unfinished area:

• The whole inner area of the room.
• Does not take reductions into account.
• Does not take calculation factors into account.

Net Room Area (NA)

The calculation of net areas is often used for planning public buildings, industrial objects and medical facilities. The net room area:

• The inner area of the room.
• Takes reductions into account.
• Does not take calculation factors into account.

Living Area (LA)

The calculation of living areas is exclusively used for planning residential buildings. The living area:

• The inner area of the room.
• Takes reductions into account.
• Takes calculation factors into account.

For rooms and subareas under roofs with a small clear height, the following calculation factors are commonly applied:

• Areas below 1 m height: 0%.
• Areas between 1 m and 2 m height: 50%.
• Balconies, terraces, winter gardens 50%.

Floor Area

The following floor areas are listed separately and summarized by levels. These area statistics are typically created for efficiency audits.

• Gross Floor Area (GFA)
• Construction Floor Area (CFA)
• Net Room Area (NRA)