Building Coverage Ratio & Floor Area Ratio

 2 Building Coverage Ratio (Building Standard Act: Article 53)

(1) ​The ratio of the horizontally projected area of a building to its land area (Building Area/Land Area) is called the building-to-land ratio, and its limit is set by city planning.

(2) If the land spans more than one area, the calculation is based on a weighted average according to the area ratio.
<Calculation Example>
In the case of a 100㎡ site with the building coverage ratios: 6/10 for 30㎡ and 4/10 for 70㎡
(30 X 6/10 + 70 X 4/10) X 1/100 = 0.46 → 46%

(3) Buildings that fall under any of the following categories are eligible to receive an increase in the building-to-land ratio.

• Properties that meet the conditions specified by the specified administrative agency, such as a property located at the corner of a city block
• Fire-resistant buildings in areas with a building-to-land ratio limit of less than 8/10 and in fire prevention zones

 3 Floor Area Ratio (Building Standard Act: Article 52)

(1) The ratio of the total floor area of a building to its land area (total floor area divided by land area) is called the "floor-area ratio," and its limit is set by city planning and other regulations.

(2) ​If the width of the road facing the property is less than 12 meters, the floor-area ratio will be limited to the smaller of the value obtained by multiplying the road width (m) by 4/10 or 6/10 and the value in (1) above.

(3) If the site extends over more than one area, the calculation is based on a weighted average according to the area ratio. (The calculation is the same as in 2(2).

(4) ​If there is a wide road (specified road) with a width of 15m or more within a distance of 70m from the site, and the width of the road facing the property is 6m or more (less than 12m), the floor area ratio (calculated according to the width of the road facing the property) can be increased.