Why One Apartment Has Three Different Sizes: A Guide to Korean Floor-Area Terms

Why does one apartment have so many sizes?

When you start looking into the Olympic Family Town redevelopment, you run into something odd. The very same unit is called 25 pyeong in one place, 34 pyeong in another, and listed as 51 pyeong on the deed. The sales brochure calls it 34 pyeong, yet the rooms feel smaller than that, and the catalog quotes a different number again: "46 pyeong of usable space."

It is one apartment, so why so many sizes? The answer is simple. Each figure counts a different boundary, that is, how much of the building is included in the measurement. Sort the terms out once and no listing or brochure will confuse you again.

First, the unit. One pyeong (평) is 3.3058㎡. Most documents now use ㎡, so it helps to remember that roughly 33㎡ is about 10 pyeong.

Area stacks up, starting from "your unit"

The principle is straightforward. You start from the innermost space, the part that is truly yours, and the number grows as you add the spaces you share. Let's walk through it with the most common size, the national standard of 84㎡ exclusive area.

1. Exclusive area (전용면적) · your actual home (84㎡, ~25 pyeong)

The space inside your front door: the interior of your unit. Rooms, living room, kitchen, and bathrooms all count here. Property tax, the comprehensive real-estate tax, subscription eligibility, and the phrase "national standard 84㎡" all use this figure. It is the first and most reliable number to check.

2. Residential common area (주거공용면적) · shared within your building (+28㎡)

Hallways, stairs, elevators, the ground-floor lobby: the shared spaces attached to your building. You can't use them alone, but you pass through them every day.

3. Supply area (공급면적) · what people usually call "34 pyeong" (112㎡, ~34 pyeong)

Exclusive area plus residential common area. When someone says they "live in a 34-pyeong unit," this is usually the figure they mean. The sale price (per pyeong) is set against the supply area too. That is why a unit whose exclusive area is about 25 pyeong gets advertised as 34.

4. Other common area (기타공용면적) · shared across the whole complex (+56㎡)

Underground parking, the management office, the senior center, community facilities: spaces the entire complex shares. The underground garage in particular is huge, which makes this figure large.

5. Contract area (계약면적) · the total on the deed and contract (168㎡, ~51 pyeong)

Supply area plus other common area, the largest figure, since it folds in your share of the parking too. It is the number that appears on the deed and the purchase contract, though people rarely use it when they casually say how many pyeong they live in.

6. Service area (서비스면적) · the balcony, a free bonus (40㎡, ~12 pyeong)

This is the balcony (veranda). The builder throws it in for free, so it doesn't factor into the sale price and isn't counted in the exclusive, supply, or contract areas. Expand it and it becomes extra living room or bedroom space. That "it is only 84㎡ exclusive, but it feels so much bigger after the expansion" effect is exactly this balcony. Note that the service area varies by architect, so even units of the same nominal size can differ between builders.

And one more you'll see in catalogs: usable area (실사용면적). It is the supply area (exclusive + residential common) plus the balcony (service), which for the 84㎡ example works out to about 152㎡, roughly 46 pyeong. That is why it feels larger than the ~34-pyeong sale figure. It isn't a legal term, though, so the exact basis differs from company to company.

The areas at a glance (national standard 84㎡)

Applying it to the Olympic Family Town redevelopment

The Olympic Family Town redevelopment is planned across a range of sizes, from roughly 32 up to 67 pyeong. Take the most common one, about 32 pyeong (84.7㎡ exclusive, ~1,500 units), and drop it into the structure above:

So the same apartment shows up as 26 pyeong (exclusive), 32 (supply), 48 (contract), and 44 (usable) all at once. Here only the exclusive and supply figures are the complex's actual numbers; the rest are calculated at typical ratios as an example. The balcony (service area) in particular varies by architect, so treat everything as provisional until the final floor plans are out.

Three things to remember when reading catalogs and listings

1. Compare unit sizes by exclusive area (㎡), always. Instead of names like "34 vs 49 pyeong," line up the exclusive ㎡ figure in the parentheses. That is the accurate comparison.
2. The sale price (per pyeong) is based on supply area. Don't mix area units when you compare.
3. Don't take "usable OO pyeong" or "OO times bigger" at face value. Since each company adds up a different set of spaces, treat these as rough reference points only.

Floor-area terms look complicated at first, but once you hold onto the single principle, start from your unit (exclusive) and add the shared spaces, most of the confusion clears up. Whether it is Olympic Family Town or any other complex, checking the exclusive area first is where an accurate comparison begins.