2026-05-30 · ~7 min read
Korean Pyeong, Explained — Why 84㎡ is Called 25-Pyeong
You're browsing apartments in Seoul. The listing says "84㎡ / 25 pyeong." Your phone calculator says 84 ÷ 3.3 = 25.45. Close enough, you think. Then you walk into the unit and it feels smaller than 25 pyeong sounded. That's because Korean real estate listings use two different area concepts at the same time — and the ㎡ ↔ pyeong conversion is the easy part.
The exact conversion (forget 3.3)
The textbook conversion most foreigners learn is "1 pyeong ≈ 3.3 ㎡." That's wrong by half a percent. The exact ratio comes from traditional Korean units:
1 ja = 10/33 m ≈ 0.30303 m
1 pyeong = 3,600 / 1,089 ㎡ ≈ 3.30579 ㎡
At a 25-pyeong apartment, the difference between 3.3 and 3.30579 is about 0.14 ㎡ — not big enough to matter. But for a 30-pyeong commercial space, it's 0.17 ㎡, which is real money in seoul. Our pyeong ↔ m² converter uses the exact ratio.
Why 84㎡ ≠ exactly 25 pyeong
Punching 84 into the converter gives 25.41 pyeong. Listings round to 25 — close enough. But why is 84㎡ such a common number in Korean listings? Because Korean apartments come in standardized sizes set by building regulations and historical convention:
| Size (㎡) | Exact pyeong | Marketed as |
|---|---|---|
| 59 | 17.85 | 18-pyeong / 20-pyeong type |
| 74 | 22.39 | 22-pyeong type |
| 84 | 25.41 | 25-pyeong type (most common 3-bed) |
| 114 | 34.49 | 34-pyeong type |
| 143 | 43.26 | 43-pyeong type |
The standardization comes from regulatory limits — 84㎡ is the largest unit eligible for certain government subsidies and tax breaks, which is why it dominates new construction.
The real trap: exclusive vs supply vs contract area
Here's where foreigners get burned. Korean listings show "84㎡" — but which 84㎡? Korean real estate uses three different area concepts:
| Type | Korean | What's included |
|---|---|---|
| Exclusive | 전용면적 | Rooms, living, kitchen, bath — what's behind your door |
| Supply | 공급면적 | Exclusive + shared residential (hallways, stairs, lobby) |
| Contract | 계약면적 | Supply + parking, management room, basement |
For a typical "84㎡ / 25 pyeong" apartment:
- Exclusive area = 84㎡ (the number on the door registry)
- Supply area ≈ 109㎡ = 33 pyeong (the number agents often quote)
- Contract area ≈ 145㎡ = 43 pyeong (what you pay property tax on)
So "25-pyeong" and "33-pyeong" can refer to the same apartment — depending on whether the seller is counting exclusive or supply area. Always ask: 전용 25평 vs 공급 33평.
How to read a Korean property listing
- Find the official ㎡ on the property registration certificate (등기부등본). This is always exclusive area — it's the only legally binding number.
- Use the pyeong converter to get the exact pyeong. (Listings round, the registry doesn't.)
- Ask the agent: "전용면적인가요, 공급면적인가요?" (Is this exclusive or supply area?) Their answer tells you which size to trust.
- Check the "전용률" (efficiency ratio) — exclusive ÷ supply. New apartments hit 70-75%. Anything under 65% means a lot of wasted shared space.
The ja² wildcard (and why it sometimes shows up)
Old Korean drawings, traditional houses, and Japanese-style architecture sometimes use ja² (尺²) instead of ㎡. Conversion:
1 ja² ≈ 0.0918 ㎡
100 ja² ≈ 9.18 ㎡ ≈ 2.78 pyeong
You probably won't see it in modern listings, but renovating a hanok (traditional house) or working from old construction drawings — ja² is what you'll meet.
Quick reference card
- 1 pyeong = 3.30579 ㎡ (not 3.3 — close enough for small spaces, off for big ones)
- 84㎡ apartment = 25.41 pyeong (exclusive) or ~33 pyeong (supply)
- Always ask: 전용 (exclusive) or 공급 (supply)
- Only ㎡ is legally binding; pyeong is for convenience
- 전용률 70%+ is decent; below 65% is wasteful
Wrap-up
Korean real estate sizes seem opaque because two systems run in parallel — but once you know that ㎡ is always exclusive and pyeong is either exclusive or supply, the listings stop lying to you. For instant conversion, use the pyeong ↔ m² converter. For Korean rental contracts and the 5% renewal cap, see the rent cap calculator.
Conversions are based on Korean traditional units (1 ja = 10/33 m). Pyeong is unofficial in Korean law since 1961; only ㎡ has legal force.