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Why 84㎡ Is 34 and 25 - Pyeong Conversion

Hand-drawn illustration of two rulers of different sizes laid side by side over one floor plan of the same home

Look at the same Korean apartment twice on a property app and the pyeong conversion has changed under you. The listing card says 34 pyeong while the detail page says an exclusive area of 84㎡, and running the numbers yourself gives 25. Is this even the same home?

Both numbers are right. Exclusive area and supply area are two different areas that count different things from the outset, and each has simply been run through the same pyeong conversion. The question is not which one is real, but which one you happen to be looking at.

Hand-drawn illustration of two rulers of different lengths laid side by side over one floor plan, the short one measuring only the rooms and living area while the long one also spans the corridor and stairwell
One home, two rulers measuring it.
Six minutes gets you
  • The reason one home is 25 pyeong and 34 pyeong at once.
  • How far off you land when you round one pyeong to 3.3.
  • Which area to check before you sign anything.
There are not two numbers. There are two areas counting different scopes.

What is going on: one home with two pyeong figures

Start with the pyeong conversion itself. One pyeong is the area of a square six ja on each side, which comes to exactly 400/121㎡, or about 3.3058㎡ in decimal form. Divide 84 by 3.3058 and you land on roughly 25.4 pyeong.

Yet the listing calls that same home a 34-pyeong unit. Nothing is miscalculated. The advertisement simply converted a number other than 84. The 25.4 comes from converting 84㎡; the 34 comes from converting a larger area altogether.

What was countedIn pyeong
Inside the front door only84㎡About 25.4 pyeong
Plus stairwells and corridors110㎡ or soLow 30s in pyeong

The two rows are not two homes. They are one home. Moving down the table, the place did not grow — the scope being counted widened.

Where exclusive area and supply area part ways

A Korean apartment mixes space you use alone with space every resident of the building shares. What you call the total depends on how much of that second kind you fold in.

Inside the front door
Exclusive area

The living room, bedrooms, kitchen and bathroom — the space you occupy on your own. This is what people mean when they talk about the real usable size. Figures such as 84㎡ or 59㎡ usually refer to this.

Beyond the front door
Supply area

Exclusive area plus stairwells, corridors and lifts — the space shared by everyone in the building. Advertised sizes usually follow this measure, which is why they look bigger than the usable figure.

So the supply area of an 84㎡ apartment is larger than 84. How much shared space gets added varies from complex to complex, which means the same 84㎡ picks up a slightly different advertised size depending on where it is. Some places call it a 33-pyeong unit, others a 35.

Hand-drawn illustration of a floor plan where the rooms and living area are shaded darkly as an inner layer, with a lighter outer layer of corridor, stairwell and lift drawn around it so the plan reads as two layers
Count the inner layer alone and you have exclusive area; include the outer layer and you have supply area.

This is also where the term exclusive area ratio comes from. It is the share of supply area taken up by exclusive area, so the higher it runs, the more space you actually use within a given advertised size.

The figure differs by complex and by building. Reading both areas listing by listing, rather than trusting one pyeong conversion, is the accurate way to go.

Can I not just divide by 3.3?

Rounding one pyeong to 3.3㎡ is a widespread habit. It is convenient, but the true value is 3.3058, so every rounded conversion drifts a little.

AreaDivided by 3.3Divided by 3.3058
84㎡About 25.45 pyeongAbout 25.41 pyeong
300㎡About 90.91 pyeongAbout 90.75 pyeong

When you are only sizing up one home, that gap is safe to ignore. What is worth remembering is that a converted pyeong figure is only ever a feel for the size. If the number is going onto a document, write the square-metre value as it stands rather than the converted one.

To check a figure straight away, drop it into the pyeong to square metre converter. It calculates with the exact 400/121 constant, and typing into either box fills the other automatically. The same page carries a quick reference table of the areas people look up most.

What changes for you

Once you know what the two figures are, the order in which you read a listing changes. The advertised size is closer to a nickname used to compare one complex against another, while the exclusive area tells you how much space you will actually live in.

Hand-drawn illustration of a property document on a desk with the line stating the area circled, next to a listing flyer whose advertised size carries a faint question mark
The document, not the advertisement, is your reference.

Whether the furniture fits and how many rooms you get are all questions about the space inside your own front door. So when you view a listing, it helps to make a habit of reading the figure written in square metres alongside the advertised size.

  • Read the square-metre figure, not just the advertised size on the card
  • Confirm what scope the area on the document actually counts
  • Compare two listings only on the same kind of area
  • Plan furniture from real room dimensions, not the advertised size

Areas on a contract and on the property register are written in square metres. If the advertised size seems at odds with the number on the paperwork, the two are most likely counting different scopes, so ask your licensed real estate agent what that number measures before you sign.

If you photographed the register and the contract on your phone while you were comparing listings, image to PDF bundles those shots into one file, which makes the areas easier to line up side by side later.

Is pyeong a unit you can no longer use?

The statutory unit of measurement for area is the square metre. Article 6(2) of Korea's Act on Measurement prohibits using a non-statutory unit in measurement or in advertising.

Article 6(3) of the same provision then allows one to be displayed alongside the statutory unit where the prescribed display requirements are met. That is the opening a pyeong conversion sits in.

Official documents and notation are therefore standardised on square metres, and pyeong lives on as a customary way of judging size. Rather than treating one as right and the other wrong, it is easier to remember that the number that goes on the record is in square metres.

If you need a ruling on a specific display obligation, check with the competent authority.

The pyeong conversion in one line

84㎡ is 25 pyeong and 34 pyeong not because the arithmetic failed, but because two areas counting different scopes were each converted. The space you will live in is the inner figure, and the number that goes on the record is in square metres.

If the figures on the listing you are looking at do not add up, put them through the pyeong to square metre converter.

References

  • Korean Law Information Center, Act on Measurement, Article 6 (Prohibition on the Use of Non-Statutory Units). View the statute
  • Korean Law Information Center, Housing Act and its subordinate regulations: classification and display standards for housing areas. View the statute
This article is general information intended to help you understand units of area and how they are written, and the statutory content in the text is current as of the time of writing (August 2026). It is not advice on property transactions, contracts or investment, and the area of any individual listing and the entries on its paperwork differ from one complex and building to another. For an actual contract, check the areas written on the property register and the contract yourself, and consult a licensed real estate agent or the competent authority on anything requiring a judgement call.

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