How to use
Type a number in either the pyeong box or the m² box and the other box is calculated. The box you typed in last is the starting value. Below the result you see the formula, a precise value rounded to 6 decimal places, and the common rule-of-thumb result (× 3.3 or ÷ 3.3). The decimal places setting (0 – 3) only changes the display; the math always uses the exact fraction.
For apartment areas, pick “Apartment areas”. Enter the exclusive area to get it in pyeong; add the supply area to also see the supply area in pyeong (the pyeong size), the residential common area and the exclusive ratio. Everything is calculated in your browser and nothing is sent to a server.
Pyeong and m² conversion formula
A pyeong is the area of a square with sides of 6 ja, and 1 ja is 10/33 m. So 1 pyeong is a square with sides of 6 × 10/33 = 20/11 m.
- 1 pyeong = (20/11 m)² = 400/121 m² ≈ 3.305785 m² (often 3.3058 m²)
- 1 m² = 121/400 pyeong = 0.3025 pyeong (exact)
- m² → pyeong: m² × 0.3025 (e.g. 40 m² × 0.3025 = 12.1 pyeong)
- pyeong → m²: pyeong × 400 ÷ 121 (e.g. 30 pyeong × 400 ÷ 121 ≈ 99.17 m²)
The popular “÷ 3.3” and “× 3.3” are rules of thumb. 84 m² ÷ 3.3 is 25.45 pyeong and 30 pyeong × 3.3 is 99 m², slightly off from the exact values. This converter shows both below the result.
Apartment area terms
Under Article 21 of the Rules on Housing Supply, the area in a Korean sales notice is stated as the residential exclusive area, and common areas may be listed separately. These are the area names you usually see.
| Term | Meaning |
|---|---|
| Exclusive area (residential exclusive area) | Space only that household uses, such as rooms, the living room, kitchen and bathrooms |
| Residential common area | Above-ground space shared by households, such as stairs, hallways and entrances |
| Supply area | Exclusive area + residential common area |
| Other common areas | Common areas other than the residential common area, such as basement levels, the management office and the senior center |
| Contract area | Supply area + other common areas |
| Service area | Additional space such as balconies excluded from exclusive and common areas. Check the sales documents for the actual classification |
Keep supply area in pyeong separate from exclusive area in pyeong. This tool shows the difference between the two entered areas as residential common area, and exclusive area ÷ supply area × 100 as the exclusive-area percentage. These terms describe the usual area categories for Korean apartments; check the definitions in the relevant documents for other building types.
Common exclusive areas in pyeong
Calculated as m² × 0.3025 and rounded to 2 decimals. All figures are exclusive areas and differ from the pyeong size (which is based on the supply area).
| Exclusive area | Pyeong |
|---|---|
| 49 m² | 14.82 pyeong |
| 59 m² | 17.85 pyeong |
| 74 m² | 22.39 pyeong |
| 84 m² | 25.41 pyeong |
| 101 m² | 30.55 pyeong |
| 114 m² | 34.49 pyeong |