The footage which can be built-upon is regulated according to a system involving two figures: and . Building coverage ratio is the ratio of the building footprint compared to the total area of the land. These two figures are often listed in advertisements for plots of land such as 70:400 (where 70 means the building coverage ratio is 70% and 400 is the floor area ratio or 400%). This would mean that a 4-story home could be built using 70% of the land. Thus, for a maximum allowable coverage ratio of 50%, the greatest building footprint allowed for a lot of 100m2 would be 50m2. Floor area ratio is the total floor area of the house (excluding the roof and basement) as compared to the area of land the house is built upon; for a maximum FAR of 150%, the greatest possible total floor area for a house built on a 100m2 lot would be 150m2. Both maximum values vary according to the location of the land and width of facing roadway, with more built-up areas with wider roads generally allowing greater maximum floorspace, and building coverage dictated by factors such as frontage, nearby roads, and construction materials. Additionally, the number of floors in a structure may be restricted, in order to avoid excessive blockage of light to neighboring properties.
