Dependants and tax

Why the calculator asks about your family

Two of the calculator’s inputs — the number of dependants (including yourself) and the number of children aged 8–20— genuinely change your tax. They are not cosmetic. In Korea, who you support lowers your tax in two distinct ways: a personal deduction that shrinks the income the tax scale ever sees, and a child tax credit that is subtracted straight from the tax itself. Change either input and the result moves immediately.

The personal deduction (인적공제)

The basic personal deduction removes ₩1,500,000 a year from your income for each qualifying person — yourself, a spouse who qualifies, and each dependent family member. Every person you add pulls the taxable base (과세표준) down by that amount, and because the scale is progressive, the saving is worth more the higher your income sits. A dependant is not a headcount for show; it is a real reduction in the base the 6%–45% scale is applied to. This is why the calculator’s dependants control counts from one — that first person is you.

The child tax credit (자녀세액공제)

Children do more than add a personal deduction: for children aged 8 and over, a separate child tax credit comes off the computed tax directly. It is ₩250,000 a year for one child and ₩550,000 for two, with a further ₩400,000 for each child beyond the second. Where a deduction lowers the income that gets taxed, a credit lowers the tax you actually owe — so a child counts twice over, once through the personal deduction and again through this credit. That combination is what makes the “children aged 8–20” box in the calculator move the result as much as it does.

What your employer actually withholds each month

There is one more reason family size matters, and it explains a difference many people notice. Your employer does not run the full annual settlement every month. Instead, monthly withholding follows the National Tax Service’s simplified withholding table(근로소득 간이세액표) — a published lookup indexed by your monthly pay, your number of dependants, and your number of children aged 8–20. More dependants on file means less tax withheld each month. You may also elect a lower or higher percentage of the table amount to be withheld, if you would rather under- or over-withhold through the year.

The table and the settlement are reconciled

The simplified table is only an approximation of your final tax; it is a convenient monthly stand-in, not the last word. At the year-end settlement(연말정산) the real annual tax is computed — the exact figure this calculator shows — and whatever was withheld month to month is trued up against it, so you receive a refund or pay the shortfall. That is why the monthly number here (the settlement tax ÷ 12) can differ slightly from what a 간이세액표-based tool prints for the same salary and family: this one anticipates the settlement rather than the monthly estimate.

The deduction and credit amounts here are transcribed from named primary sources and are the ones in force for 2026; a very recent change may not have reached this page yet, and none of them has been through this site’s own review and sign-off — for the amount that binds you, check with your employer or the National Tax Service.

The content of this page is still being expanded.