The statute sets out the arithmetic plainly enough. For a single household: "below 4m won, earnings counted × 165/400", and so on. But the figure that arithmetic produces is not what gets paid. The last paragraph of the same article says why.
"Notwithstanding paragraphs (1), (2) and (4), the credit shall be calculated by applying the benefit table prescribed by Presidential Decree, drawn up by band of earnings counted."
— Restriction of Special Taxation Act, art. 100-5(5)
So the formula is the basis on which the table is drawn; the amount itself comes from table 11 of the Enforcement Decree. We opened that table and worked out the rule behind it.
The rule is one sentence
Within each band, apply the statutory formula at whichever end gives the larger figure, then round up to the nearest 1,000 won.
The formula rises, plateaus and falls, so in practice that means the top of a rising band and the bottom of a falling one.
A few rows will show it. On the rising side a single household's coefficient is 1.65m ÷ 4m = 0.4125.
| Band | Published figure | Rebuilt |
|---|---|---|
| 40,000 ~ 70,000 | 29,000 | 70,000 × 0.4125 = 28,875 → up to 29,000 |
| 100,000 ~ 200,000 | 83,000 | 200,000 × 0.4125 = 82,500 → up to 83,000 |
| 3,000,000 ~ 3,100,000 | 1,279,000 | 3,100,000 × 0.4125 = 1,278,750 → up to 1,279,000 |
| 9,100,000 ~ 9,200,000 | 1,638,000 | bottom end 9,100,000 → 1,637,308 → up to 1,638,000 |
| 9,400,000 ~ 9,500,000 | 1,600,000 | bottom end 9,400,000 → 1,599,230 → up to 1,600,000 |
| The first three are rising bands, priced at the top; the last two are falling, priced at the bottom. Figures from Decree table 11; the rebuilding is ours. | ||
Values built this way were checked against 70 rows, with a single cell out of place — recorded below. One earner (2.85m ÷ 7m) and two earners (3.3m ÷ 8m) rebuild the same way.
Which is why the table sits 100,000 won off the statute
The Act says a single household gets 1.65m won "from 4m won up to 9m won". The table already pays 1.65m won from the 3.9m won band — because the top of that band is 4m won.
The other end mirrors it. Tapering should begin at 9m won; in the table the bottom of that band is 9m won, so the figure holds and the decline only starts 100,000 won later. One earner reaches its maximum at 6.9m won, two earners at 7.9m won.
A formula-based calculator under-reports
Take a single household with earnings counted of 3.8m won.
| Method | Result |
|---|---|
| The statutory formula as written | 1,567,500 won |
| The benefit table (band 3.8m ~ 3.9m) | 1,609,000 won |
| Difference | 41,500 won |
| The widest gap on the rising side is 42,000 won (our calculation). | |
There is nowhere the table pays less than the formula — it always takes the largest figure in the band.
Where one earner receives exactly the single amount
The rising slope is steeper for a single household: 1.65m/4m = 0.4125 against 2.85m/7m ≈ 0.4071. Follow the statutory formula and, at low earnings, one earner would receive less than single.
The table simply writes the single figure into the one-earner column there. The two columns are identical, row for row, up to earnings counted of 4m won, and part in the very next band (4m ~ 4.1m) at 1,650,000 against 1,670,000.
The table stops before the income ceiling
On the statute the single household's taper reaches zero at 22m won. The table is already blank from 21,881,900 won, where the formula gives 14,989 won — short of 15,000 won.
Around there the bands stop being 100,000 won wide: 70,000, then 30,000, then one of 81,900 — cut, it appears, to land exactly on the stopping point.
We found the provision — art. 100-7(3). "Where the amount calculated under Article 100-5 is less than 15,000 won, it shall be determined that there is no credit." The boundary 21,881,900 won matches the point where the formula equals exactly 15,000 won, rounded up to the nearest 100 won.
The same reason explains why the table does not start at zero either. Its first row begins at 40,000 won, and for a single household the rising formula reaches 15,000 won at earnings counted of 36,364 won. The end is rounded to the nearest 100 won and the start to the nearest 10,000 — we did not find anything in the statute explaining the different precision.
And a statutory minimum sits after the table
The same paragraph adds two more branches.
| Which part of the curve | Calculated amount | Determined as |
|---|---|---|
| Rising (item (a)) | 15,000 won to 100,000 won | 100,000 won |
| Tapering (item (c)) | 15,000 won to 30,000 won | 30,000 won |
| Which means some rows of the table are not the final figure — the first three for a single household (29,000, 42,000 and 83,000 won) are all determined as 100,000 won. | ||
So the order runs: statutory formula → benefit table → asset reduction → (95% if late) → statutory minimum. The table is one step among several.
One cell the rule does not reproduce
Across 70 rows, exactly one disagreed.
| Household | 21,700,000 ~ 21,770,000 | 21,770,000 ~ 21,800,000 |
|---|---|---|
| Single | 39,000 | 30,000 |
| One earner | 1,631,000 | 1,631,000 |
| Two earners | 2,726,000 | 2,717,000 |
| By the rule the right-hand one-earner cell should read 1,620,000. The two-earner row was recalculated at the split band's lower end; only the one-earner row keeps the value from before the split. | ||
We read the original twice at magnification. The table is the more generous of the two, so nobody loses by it. We may also have misread it, so we record it as printed.
Questions that tend to remain
Then why is the formula in the Act at all?
It is the basis the table is drawn from. Changing a maximum or a band edge takes an amendment to the Act, and the Decree redraws the table to match. The table cannot move while the formula stands still.
Why the favourable end?
The statute does not say so — it is a rule we recovered from the table. Grouping into bands forces a choice of one figure per band, and the choice made is the one that favours the claimant. The 1,000-won step is rounded up, not to nearest.
Does anyone lose out from 100,000-won bands?
No. Everyone in a band receives its largest figure, so within a band the lower earner does relatively better. Someone on 3,000,000 and someone on 3,090,000 receive the same amount.
How far was the rule checked?
We read the table up to earnings counted of 21.9m won. That covers every transition — rising, plateau and taper — for all three household types, and for the single household it reaches the point where the table ends. The last pages for one and two earners are still unread.
Sources
Restriction of Special Taxation Act, in force 1 January 2026 (Act 21223), art. 100-5 — (1) the formulas, (2) half-year claims, (4) the asset reduction, and (5) the primacy of the table.
Enforcement Decree, in force 1 July 2026 (Presidential Decree 36423), table 11, the benefit table (under art. 100-6(5), amended 28 February 2025).
Read at magnification in the annex viewer on the national statute portal. Rebuilt figures were compared with 70 of its rows, and the one cell that disagreed is set out above.
Where to check
The national statute portal — Enforcement Decree table 11. The whole table is there to read.
Hometax. Where the actual assessment is made.
To put a number on it, the calculator uses exactly this rule. Definitions are in household type and the two meanings of income, and the overview is in the earned income and child tax credit guide.
