Most guides to Korea's earned income tax credit stop at the three headline figures — 1.65m won for a single household, 2.85m won for one earner, 3.3m won for two. Those are maximums. What actually arrives depends on which band your earnings counted fall into, and the bands are set out in table 11 of the Enforcement Decree to the Restriction of Special Taxation Act.
1. Working the statutory formula under-reports the benefit. Article 100-5(5) says the table applies notwithstanding the formula. On earnings of 3.8m won a single household gets 1,609,000 won from the table where the formula gives 1,567,500 won — 41,500 won apart.
2. There are two asset thresholds, not one. Eligibility ends at 240m won, but the benefit is already halved at 170m won.
3. A statutory minimum sits after the table. On the rising side a calculated amount between 15,000 won and 100,000 won is determined as 100,000 won; on the tapering side, between 15,000 won and 30,000 won it becomes 30,000 won (art. 100-7(3)).
4. "Annual total income" and "earnings counted" are different numbers. The first decides whether you qualify, the second decides how much — interest, dividends and pension enter only the first.
Give it a household type and an earnings figure and it returns what the table sets. Add assets and it applies the reduction too.
It uses the table, not the formula. The figures follow the rule behind Enforcement Decree table 11 — each band priced at whichever end favours the claimant, rounded up to the nearest 1,000 won. You have to supply the earnings figure yourself: business income enters only after its sector rate is applied. Annual total income (eligibility) and earnings counted (the amount) are different numbers. The statutory minimum in art. 100-7(3) (100,000 won on the rising side, 30,000 on the tapering side, nothing below 15,000) and the 95% for a late claim are applied. Half-year claims, the dependent-child test, the exclusions, and offsetting against unpaid national tax are not included. An estimate — the real figure is set by the tax office.
What this calculator does
Rather than transcribing an eleven-page table, it uses the rule that generates the table. 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.
Because the formula rises, plateaus and then falls, that means the top of a rising band and the bottom of a falling one.
Values built from that rule were checked row by row against 70 rows of the published table, with nothing out of place — all three household types, both the rising and the falling side. The working is in why the formula and the table disagree.
The three curves turn at different points
Same shape, different corners. A single household ramps to 4m won and 1.65m won, then tapers from 9m won. One earner: 7m won, 2.85m won, 14m won. Two earners: 8m won, 3.3m won, 17m won.
| Household | Reaches maximum | Maximum | Starts to taper | Reaches zero |
|---|---|---|---|---|
| Single | 4m won | 1.65m won | 9m won | 22m won |
| One earner | 7m won | 2.85m won | 14m won | 32m won |
| Two earners | 8m won | 3.3m won | 17m won | 44m won |
| Act art. 100-5(1). The last column carries the same figures as the income ceilings but measures something different — set out below. | ||||
The two-earner column is simply empty below 6m won. A two-earner household needs 3m won from each spouse (art. 100-3(5)3), so the combined figure cannot be lower. The statute and the table line up exactly.
Assets catch you twice
The asset test is easy to remember as a single line at 240m won. There is another one before it.
Household assets of 170m won or more cut the benefit to 50% (art. 100-5(4)). At 240m won or more there is no eligibility at all (art. 100-3(1)4). A single household on the maximum goes from 1,650,000 won to 825,000 won, and then to nothing.
Both lines are strict, so the exact figure decides — one won short of 170m won and the benefit is whole; level with it and it halves.
The table always pays more than the formula
Pricing each band at its favourable end means you receive the largest figure in your band wherever you sit inside it. The gap is widest on the rising side, reaching 42,000 won.
So a calculator built from the statutory formula reports less than is actually paid. That is why this one follows the table's rule instead.
After the table there is a separate determination
The table is the calculation. The determination comes after it (art. 100-7(3)), in three branches.
| Which part of the curve | Calculated amount | Determined as |
|---|---|---|
| Anywhere | below 15,000 won | no credit |
| 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 |
| Act art. 100-7(3). The test is applied after the asset reduction (art. 100-5(4)) and the 95% for a late claim (art. 100-7(2)). | ||
For a single household the guarantee actually raises the figure from earnings counted of 40,000 won up to 200,000 won. Those are the three rows where the table reads 29,000, 42,000 and 83,000 won — every one of them is determined as 100,000 won. Easy to give up on after reading the table alone.
Read literally, the provision can lower the figure. It says the credit "shall be determined as 100,000 won", not "shall be at least 100,000 won". At earnings counted of 200,000 won the table gives 124,000 while the item (a) calculation gives 99,000 — so the literal reading lands on 100,000 won. We read it as a floor and applied it only upwards, and we are recording that this was our choice.
Questions that tend to remain
What goes into "earnings counted"?
Three things: employment income, religious workers' income, and business income after its sector rate (art. 100-3(5)3). Interest, dividends, pension and other income do not. Business income enters at its adjusted figure, not at turnover — the sector rates run from 20% to 90%. All ten are listed in household type and the two meanings of income.
Why enter annual total income separately?
Because that is the figure the eligibility test uses. However low your earnings, enough interest, dividends or pension can push annual total income over the ceiling and end the claim. The same numbers (22m won, 32m won, 44m won) appear in both places and measure different things.
If both spouses work, is it automatically a two-earner household?
No. The statute asks for 3m won or more of earnings counted from each spouse. A spouse who earned 2.5m won leaves you in the one-earner category — which has a lower maximum but pays more than two-earner status over part of the range.
How does the half-year claim work?
First-half income is annualised, run through the same bands, and 35% of the result is paid early (art. 100-5(2)1). The annualisation is first-half employment income ÷ months worked × (months worked + 6), where a month counts only if it carried 15 days or more of work (Decree art. 100-6(3)). This calculator assumes the ordinary May claim.
What if the calculator and the assessment disagree?
Start with the earnings figure you entered — the sector rate on business income, the spouse's earnings added in (art. 100-5(3)), and the excluded categories are where it usually goes wrong. Unpaid national tax can also be set off against up to 30% of the benefit (art. 100-8(4)).
Sources
Restriction of Special Taxation Act, in force 1 January 2026 (Act 21223) — arts. 100-3 (eligibility, household type, earnings counted), 100-4 (dependent children), 100-5 (calculation, asset reduction, half-year), 100-6 (claiming), 100-8 (refund and set-off).
Enforcement Decree, in force 1 July 2026 (Presidential Decree 36423) — art. 100-3(1) (annual total income and the sector rates), art. 100-6 (months worked), and table 11, the benefit table (under art. 100-6(5), amended 28 February 2025, eleven pages).
The provisions and the table were read directly on the national statute portal. The table was read at magnification in the annex viewer, and figures rebuilt from the rule we found were checked against 70 of its rows — all three household types, both sides of each curve, and the point where the table stops.
The calculator's script was checked against the same model — 306 combinations of household, earnings, assets and claim timing, all matching.
Where to check
Hometax — the claim itself. It is worked from the income records the tax office already holds.
The May filing window. The ordinary claim is made then, and only alongside an income tax return (art. 100-6(5)).
The tax helpline, 126. Fastest route when the household classification is unclear.
For the wider picture and the child credit, see the earned income and child tax credit overview; for business income, global income tax and the 3.3% withholding. Where these figures come from is in formula versus table, and the definitions are in household type and the two meanings of income.
