A Unit That Survived Its Own Abolition
Korea legally switched to the metric system for property in 2007, and using pyeong in an official document has been prohibited since. Nearly two decades later, every listing, every conversation and every price comparison still runs on it. A Korean buyer hears "84 square metres" and mentally converts to 34 pyeong before the sentence finishes.
The unit came from the Japanese tsubo during the colonial period and is roughly the floor area two people need to lie down, which is why it maps onto how a home feels in a way a square metre does not.
The exact conversion
One pyeong is 3.305785 square metres, and the constant is not arbitrary. A pyeong is a square six cheok on each side, and one cheok is defined as 10/33 of a metre. Six of those is 60/33 metres, and squaring it gives 3600/1089, which is 3.305785 recurring.
- Pyeong to square metres: multiply by 3.305785.
- Square metres to pyeong: divide by 3.305785.
The shortcut Koreans use in conversation is to multiply pyeong by 3.3, which is accurate enough to within about 0.2%. For a contract, use the full constant.
The Distinction That Actually Costs Money
Getting the arithmetic right is the easy half. The half that matters is knowing which area a number refers to, because Korean listings quote two and they differ by a quarter.
공급면적 (supply area) includes your unit plus a share of hallways, stairwells, lift lobbies and wall thickness. This is the pyeong figure used in conversation and in most advertising.
전용면적 (exclusive area) is the space inside your own front door. This is what appears on the registry and what you actually live in.
The ratio between them, 전용률, the efficiency ratio, typically runs 75% to 85%. An older tower block with generous corridors sits at the bottom of that range; a newer building with an efficient core sits at the top. Two apartments advertised as the same pyeong can therefore differ by several square metres of actual living space, and the efficiency ratio is the number that tells you which is which.
| Pyeong (supply) | Supply area | Exclusive area at 80% | Typical layout |
|---|---|---|---|
| 10 | 33 m² | ~26 m² | Studio or one room |
| 18 | 60 m² | ~48 m² | Small two-bedroom |
| 24 | 79 m² | ~63 m² | Two to three bedrooms |
| 34 | 112 m² | ~90 m² | The standard family apartment |
| 45 | 149 m² | ~119 m² | Large family apartment |
| 60 | 198 m² | ~159 m² | Premium or penthouse |
The 34-pyeong line is worth knowing on its own. It is the default family apartment in Korea, so common that "34평" functions as a category rather than a measurement, and the 84 m² exclusive area associated with it is the single most quoted figure in the Korean housing market.
Reading a Korean Listing
Prices are usually quoted per pyeong (평당가격), which makes apartments of different sizes directly comparable within a neighbourhood and is the fastest way to tell whether an asking price is in line with the building next door.
Land follows the same unit: a 100-pyeong lot is about 330 m², or roughly 3,553 square feet. And when a listing gives both numbers, the smaller one is the exclusive area, if it is not labelled, the ratio between the two tells you which is which.
This converter handles the arithmetic in both directions. What it cannot tell you is which area a particular listing means, so where a figure has contractual consequences, confirm against the registry entry rather than the advertisement.