You've probably done this: open a property app, line up two apartments side by side, and squint. One's 900 million won, the other 1.1 billion. Both listed as '34 pyeong.' Same size, supposedly — so why does one look roomier?

The total price alone won't answer that. Both listings use the same word, 'pyeong,' but the standard behind that word can differ. Here we'll work through how to put one ruler in your hand — price-per-pyeong — to line complexes up in a row. And why that ruler isn't a cure-all.

Price-per-pyeong: one division, that's it

Price-per-pyeong is exactly what it sounds like: the price per one pyeong (3.3㎡). Take the total price, divide by the area in pyeong, done. A 900-million-won home at 30 pyeong? 900 million ÷ 30 = 30 million won per pyeong.

Why bother dividing? The total only says 'how expensive this home is.' Price-per-pyeong goes a step further — it tells you how much you pay for the same chunk of space. It's the conversion device that lets you set a big home next to a small one, an expensive neighborhood next to a cheap one, on the same scale.

And this is exactly where people get fooled. Depending on which 'area' you feed it, the same home's price-per-pyeong jumps around. It comes down to one thing: exclusive area versus supply area.

Exclusive or supply?

Two area figures show up for the same apartment because 'how much counts as my space' isn't settled.

• Exclusive area — The space your family alone actually walks around in once the front door shuts. Rooms, living room, kitchen, bathroom. Entirely yours.
• Shared residential area — Stairs, hallways, elevators. The parts residents of the same building share.
• Supply area — Exclusive area plus shared residential area. This is usually the standard behind 'so many pyeong' in a sales ad or listing.

So '34-pyeong type' usually means supply area, and the exclusive area you actually live on is smaller than that. The share exclusive area takes within supply area is the exclusive-area ratio. The higher it is, the more usable space you get for the same nominal size.

Same 34 pyeong, one feels bigger?

Back to the opening puzzle. Both homes are '34 pyeong,' yet one feels roomier — here's the reason.

Say complex A is a corridor-type building with wide shared space, and complex B is a stairwell-type with narrow shared space. Supply area is 34 pyeong for both. But B's exclusive area can be larger. Same supply-area price-per-pyeong, different space underfoot.

So one rule. When you compare price-per-pyeong, you compare like area standard with like. No exceptions.

• Supply-area price-per-pyeong against supply-area only.
• Exclusive-area price-per-pyeong against exclusive-area only.
• Mix the two and the exclusive-area ratio gap walks right in as an illusion.

Take the same 900-million-won home. Divide by a 34-pyeong supply area and you get about 26.5 million won per pyeong; divide by a 25-pyeong exclusive area and you get about 36 million won per pyeong. Same home, just a different basis, and the number swings by nearly ten million. So when someone says 'A is cheaper per pyeong than B,' the first thing to fire back is: "Which area standard is that?"

Pyeong and square meters, in your head

The official notation now is square meters (㎡), but in actual conversation 'pyeong' still rolls off the tongue. Move between the two freely and no listing will throw you.

1. 1 pyeong ≈ 3.3㎡. Precisely it's 3.305785㎡, but 3.3 is plenty for a rough cut.
2. ㎡ to pyeong: divide by 3.3. 84㎡ → 84 ÷ 3.3 ≈ 25 pyeong.
3. Pyeong to ㎡: multiply by 3.3. 34 pyeong → 34 × 3.3 ≈ 112㎡.

One more thing. Common figures like '84㎡' or '59㎡' usually mean exclusive area. That's why an ad's '34-pyeong type (supply)' and a registry's 'exclusive 84㎡' often point to the very same home. Checking the unit and the standard together — that's the habit that guards you against the illusion.

Lining up neighborhoods and complexes

The real payoff of price-per-pyeong is putting different things on the same row. Totals of 900 million and 1.1 billion are hard to weigh in your head; 30 million per pyeong versus 34 million per pyeong land instantly.

But the comparison only means something if you match conditions. Same area standard is the floor, and ideally you compare similar size ranges. It's observed on record that smaller units tend to carry a higher price-per-pyeong than larger ones, generally. Smaller homes looking pricier per unit of area is a common pattern.

And yet price-per-pyeong isn't a cure-all

It's a powerful ruler, no argument. But it can't catch every difference. Even within the same complex, same size, same area standard, prices vary home to home — and for real reasons.

• Floor — At the same size, a low floor and a prime floor are valued differently.
• Orientation — South-facing versus north-facing changes the light and the feel.
• Age and condition — At the same size, a new build and an aging complex get assessed differently.
• View and building position — Even inside a complex, whether the building ahead blocks your view matters.

This is the spot I personally trip over most. Set the big picture with price-per-pyeong, sure — but it can't be the whole of a final call. Sort the row with price-per-pyeong first, then filter again within it by floor, orientation, age. A two-step way of looking.

Today's takeaway

Price-per-pyeong is a conversion device for 'how much for the same chunk of space.' The key is to always compare on the same area standard (exclusive with exclusive, supply with supply) and among similar conditions.

This piece isn't here to hand you an answer. It's here to put one ruler in your hand — so that in front of a listing you can ask yourself, "Which area standard is this?" and "What's there beyond price-per-pyeong?"