Floor Area Ratio Calculator

Floor Area Ratio Calculator. The Floor Area Ratio (FAR) measures how much total building floor space exists relative to the land it sits on — a critical figure in zoning, urban planning, and real estate development. Enter your Gross Floor Area and Plot Area to get the Floor Area Ratio, along with Built-up Area, Super Built-up Area, Open Space Ratio, and Loading Factor. Optionally add Carpet Area, Area of Walls, Common Area, and Number of Units for a more complete breakdown. Also try the Laminate Flooring Calculator.

Floor Area Ratio Calculator inputs
sq ft

Total floor area of all floors in the building

sq ft

Total area of the land parcel

sq ft

Usable floor area that can be covered with carpet

sq ft

Total area occupied by internal walls

sq ft

Shared spaces like lobby, corridors, elevators

Total number of residential/commercial units

Results

Floor Area Ratio (FAR)

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Built-up Area

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Super Built-up Area

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Open Space Ratio (OSR)

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Loading Factor

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What is Floor Area Ratio (FAR)?

Floor Area Ratio (FAR) is the ratio of total gross floor area of a building to the total area of the plot on which it is constructed. It indicates the building density and is used by planning authorities to regulate development. See also our use the Epoxy Floor Calculator.

How do you calculate Floor Area Ratio?

FAR is calculated by dividing the total gross floor area of all floors by the total plot area. For example, if a building has 2,500 sq ft of floor area on a 1,000 sq ft plot, the FAR is 2.5.

What is the difference between carpet area and built-up area?

Carpet area is the usable floor space that can be covered with carpet, excluding walls and common areas. Built-up area includes carpet area plus the area occupied by walls and internal structures.

What is super built-up area?

Super built-up area includes built-up area plus a proportionate share of common areas like lobbies, corridors, elevators, and amenities. It represents the total area you pay for when buying a property.

Why is FAR important for property development?

FAR determines how much construction is allowed on a plot. Higher FAR allows more floor space, increasing development potential and property value. It helps developers understand zoning regulations and maximum buildable area.

What is Floor Space Index (FSI)?

Floor Space Index (FSI) is another term for Floor Area Ratio (FAR). Both represent the same concept - the ratio of total built-up area to the plot area. Different regions may use different terminology.

How does loading factor affect super built-up area?

Loading factor is the percentage of common area added to carpet area. It typically ranges from 15-30%. Super built-up area can be calculated as carpet area multiplied by (1 + loading factor percentage).

What is Open Space Ratio (OSR)?

Open Space Ratio (OSR) is the percentage of plot area that remains open and unbuilt. It's calculated as (Plot Area - Built-up Area) / Plot Area × 100. Higher OSR indicates more open space around the building. You might also find our Floor Joist Calculator useful.