There is a reason the standard Korean apartment is 84㎡. Cross 85㎡ of exclusive floor area and the tax notice gains a line — the special rural development surtax. On a KRW 900m home that is 1.8m won; under the 12% heavy rate, 9m.
85㎡ or less is exempt. Over it, the surtax applies — 0.2% at standard rates, 0.6% under the 8% heavy rate, 1.0% under 12%.
The formula is not the acquisition rate but “10% of the acquisition tax computed at 2%” (Rural Special Surtax Act art. 5(1)6). Under a heavy rate, the amount the heavy rate added goes on top of that 2% — 4 points at 8%, 8 points at 12%.
Applying 10% to the whole acquisition rate is wrong — that gives 0.8% and 1.2%, where the right answers are 0.6% and 1.0%.
What 0.1㎡ is worth
84.9㎡ against 85.1㎡. Same rate, different area.
| Price | One home (0.2%) | 8% heavy (0.6%) | 12% heavy (1.0%) |
|---|---|---|---|
| KRW 500m | 1m | 3m | 5m |
| KRW 900m | 1.8m | 5.4m | 9m |
| KRW 1.2bn | 2.4m | 7.2m | 12m |
Acquisition tax and education tax do not look at floor area at all. This is the only line that does. So at the same price, 84㎡ and 85.1㎡ produce different notices.
Why 2% rather than the actual rate
The surtax rides on the acquisition tax but does not follow the acquisition rate. The statute fixes it at “10% of the tax computed at 2%.”
| Acquisition rate | Base for the surtax | Surtax rate |
|---|---|---|
| 1% (one home, up to 600m) | 2% | 0.2% |
| 2.3333% (one home, 800m) | 2% | 0.2% |
| 3% (one home, over 900m) | 2% | 0.2% |
| 8% (heavy) | 2% + 4 points | 0.6% |
| 12% (heavy) | 2% + 8 points | 1.0% |
Look at the middle three rows. The acquisition rate triples from 1% to 3% and the surtax stays fixed at 0.2%. “It is a surtax, so it must be proportional to the main tax” breaks here.
Only the heavy rates change it, and even then it is not the whole rate but the amount the heavy rate added that goes on top of the 2%. Multiplying 8% by 10% gives 0.8%, and that is the wrong figure.
The education tax moves the other way
The two surtaxes on the same notice behave differently.
| Local education tax | Rural development surtax | |
|---|---|---|
| Floor area | ignored | over 85㎡ only |
| Standard band | tracks the rate (0.1–0.3%) | fixed at 0.2% |
| Heavy 8% · 12% | fixed at 0.4% | splits 0.6% · 1.0% |
| Source | Local Tax Act art. 151 | Rural Surtax Act art. 5(1)6 |
In the standard band the education tax tracks and the rural surtax is fixed; under the heavy rates the education tax is fixed and the rural surtax splits. Exactly inverted. Bundling both as “the surtaxes” hides that structure.
Questions that remain
How big is an 84㎡ apartment exactly?
It varies by development. An “84㎡ type” is registered as 84.87㎡, 84.96㎡ and so on — always 84-point-something, designed not to cross 85. That is the design. Do not confuse it with supply area — a unit sold as 112㎡ is commonly 84㎡ exclusive. The test is exclusive area.
What about exactly 85㎡?
The charge applies above 85㎡, so exactly 85 is exempt, and the calculator treats it that way. How the decimals are handled in practice we could not verify — if a property sits between 85.00 and 85.01, ask the local authority first.
I heard the threshold differs outside the capital region.
The definition of “national housing scale” is described as carrying an exception of 100㎡ for eup and myeon areas outside the capital region. Whether that exception carries into the rural surtax exemption we could not verify against the statute. If it might apply, confirm with the local authority — there are millions of won in it.
Does the 85㎡ test apply to officetels?
An officetel is described as taxed at 4% as non-residential property rather than as a home, so the whole rate structure differs and this table cannot be transferred to it. How one used as a residence is treated we could not verify — we know only what is set out in the acquisition tax guide.
When is the rural surtax paid?
With the acquisition tax. There is no separate notice; it appears as a line on the same one. So when the acquisition tax “seems higher than expected,” what is usually being read is the total with this and the education tax included. The calculator separates all three.
Sources and where to check
Rural Special Surtax Act art. 5(1)6 — 10% of the acquisition tax computed at 2%, with the heavy-rate addition layered onto that 2%. Housing at national housing scale (85㎡ or less) is described as exempt.
Local Tax Act art. 151 — local education tax: (standard rate × 50%) × 20% for a home purchase, 0.4% under the heavy rates.
The rates were cross-checked against two unrelated sources. This site’s acquisition tax guide left the rural surtax blank as “a separate act, so the rate is not copied here” — this article fills that gap. The statute itself could not be opened — the national law portal blocks automated retrieval.
Where to check further
The exclusive area on the register or the contract. Not the supply area. It is written to the decimal.
The Wetax acquisition tax calculator. The safest check on the actual assessment.
For an eup or myeon area, the local authority. Whether the 100㎡ exception reaches this surtax is unverified.
To see all three taxes together, enter the floor area in the acquisition tax calculator. If the price is between 600m and 900m, read the marginal rate inside the slope alongside it.
