Korean listings show “exclusive area” (전용면적). Older ads use “supply area” in pyeong, which includes shared space — e.g., 84㎡ exclusive is usually sold as a “34-pyeong” apartment.
Example: an 84 ㎡ apartment is 84 × 121 ÷ 400 ≈ 25.41 pyeong, or about 904 sq ft. In reverse, 30 pyeong is 30 × 400 ÷ 121 ≈ 99.17 ㎡. One pyeong is defined as exactly 400/121 ㎡ (about 3.3058 ㎡ or 35.58 sq ft).
Why "34 pyeong" listings are only 84 ㎡: Korean apartment sizes in ads (평형) use the supply area, which adds shared spaces such as stairs and corridors to the exclusive area (전용면적). An 84 ㎡ exclusive-area flat is therefore marketed as a 33–34 pyeong type, and a 59 ㎡ flat as a 24–25 pyeong type.
Common mistakes
Always compare homes by exclusive area in ㎡ (전용면적). Mixing exclusive and supply areas makes flats look bigger or smaller than they are.
Balcony extensions are not counted in the exclusive area, so two 84 ㎡ flats can feel different in size.
Officetels (오피스텔) often quote a contract area that includes even more shared space, so the same "pyeong" means less living space than in an apartment.
Square metres are the official unit in Korea; contracts and public notices use ㎡.
Prices quoted "per 3.3 ㎡" are read as per-pyeong prices, but one pyeong is about 3.3058 ㎡, so totals differ slightly.
If the land registry and the building register disagree on area, the building register figure is normally used.