Free word search
Category
Exclusive vs. Total Floor Area: What’s the Difference and How They’re Calculated
2026.01.29
.png)
When purchasing or renting a property, many people use “area” as one of the key indicators. In this column, we explain the difference between exclusive floor area and total floor area, both of which describe a building’s size.
What Is Exclusive Floor Area?
In collective housing such as condominiums and apartments, residents share spaces within the premises with others. Elevators, hallways, entrances, and staircases used by all residents are called common areas, while living rooms, kitchens, toilets, and other interior spaces that only each resident can use are called exclusive areas.
Exclusive floor area refers to the total area of these exclusive spaces. In other words, it represents the size of the private living space you actually occupy.
Although balconies may seem like private areas, they are considered common areas because they must be available for shared use in emergencies such as fires.
Difference Between Exclusive Floor Area and Total Floor Area
A term often confused with exclusive floor area is total floor area (延床面積). Total floor area refers to the combined floor space of the entire building.
For example, in a three-story building, the total of the floor areas from the 1st to the 3rd floors constitutes the total floor area. Since it is calculated across all floors and includes common areas, this measurement is more relevant for detached houses than for single-floor apartments.
Total floor area only includes spaces enclosed by exterior walls or the inner side of structural columns. However, open spaces such as double-height voids (atriums) are excluded because they have no flooring, and porches are excluded as well because they lie outside the building’s interior.
Similarly, balconies, verandas, and terraces are not included unless their depth exceeds two meters from the exterior wall, meaning that most exterior structures are excluded from total floor area.
.png)
Areas Not Included in Exclusive Floor Area
Exclusive floor area includes only the exclusive-use spaces. Therefore, balconies, verandas, staircases, entrances, and hallways—which are common areas—are not included.
Lofts are also excluded if the ceiling height is 1.4m or less and the loft floor area is less than half the size of the floor below, as they are classified as “attic storage.” If the ladder is not fixed in place, the loft is also excluded from total floor area.
How Exclusive Floor Area Is Calculated
There are two methods for calculating exclusive floor area: wall-center measurement (壁芯) and interior-wall measurement (内法).
・Wall-center area (壁芯面積)
This method measures area using the centerline of the surrounding walls. Because half the wall thickness is included, the displayed area tends to be larger than the actual usable space. Real estate listings typically use this method.
・Interior-wall area (内法面積)
This method measures only the inside surface of the walls, excluding wall thickness, making it closer to the actual usable living space.
Recommended Exclusive Floor Area for Comfortable Living
For single occupants, 1K or studio apartments of 15–20㎡ are common, and in recent years, compact units around 10㎡ have also become popular. These ultra-compact units often include lofts, which are not counted in the exclusive floor area.
The Ministry of Land, Infrastructure, Transport and Tourism (MLIT) has set minimum living space standards in its “Basic Plan for Housing.” According to this, the minimum necessary area for a healthy and cultural lifestyle is 25㎡ for one person and 30㎡ for two people.
While these are minimum guidelines, many properties fall below these numbers in reality. For example, in a 25㎡ apartment, a typical layout includes a separate bath and toilet, a sink area with space for changing clothes, and storage, with the main living space measuring around 6–10 tatami mats. For a single occupant, this size generally feels sufficient.
Related Articles
.png)
.png)