Korean Child Tax Credit Calculator

This calculator works out the child tax credit, the amount knocked off your Korean income tax for having children, in the year-end settlement or the annual return. Enter the tax year, the number of children at or above the qualifying age, whether a child was born or adopted that year, and your computed tax, and it shows the credit by number of children, the birth or adoption credit, their sum and the amount you actually receive after the tax ceiling.

This is a tax credit, not an income deduction. It comes straight off the tax already computed, so it lowers your bill by a fixed amount whatever your rate. The flip side is that a credit larger than your tax is not refunded; the excess simply vanishes. That is why the calculator asks for your computed tax.

Employees and self-employed parents use it before filing their year-end paperwork. It matters most when a child has just reached the qualifying age, when a baby arrived during the year, or when a dual-income couple must decide which parent claims the children, because knowing the figure lets you pick the better side.

It matters even more now because the qualifying age changes every year. The threshold is moving from 8 to 13, rising one year at a time from 2026 to 2029, so a child who qualified last year may drop out this year. Changing the tax year in the calculator shows how many children qualify in each year.

The rule is 소득세법 제59조의2. Paragraph 1 grants, by the number of children and grandchildren who are basic-deduction dependants at or above the qualifying age, ₩250,000 for one child, ₩550,000 for two, and a further ₩400,000 for each child from the third, so three children give ₩950,000. Paragraph 3 adds, for a child born or adopted that year, ₩300,000 for a first child, ₩500,000 for a second and ₩700,000 for a third or later; this credit ignores age and is claimed alongside the paragraph 1 credit.

The qualifying age is not a single number. The main text says 13 and over, but transitional provisions phase it in: 9 and over for 2026, rising one year at a time to 12 and over for 2029, then 13 from the following year. Up to the 2025 tax year it was 8. Age is measured at 31 December of the tax year. The calculation takes the paragraph 1 credit for the number of qualifying children, adds the birth or adoption credit, and compares the total with the computed tax, the smaller of the two being the actual credit.

With the default of two qualifying children the credit is ₩550,000. If a third child was born in the same year, the ₩700,000 birth credit is added for ₩1,250,000. The newborn is below the qualifying age and does not count toward the paragraph 1 headcount, but the birth credit applies regardless.

Three qualifying children make ₩950,000 available. If the computed tax is only ₩500,000, though, the actual credit stops at ₩500,000 and ₩450,000 is lost. In that situation a dual-income couple should claim the children on whichever spouse has the larger computed tax, and the calculator's "lost to the tax ceiling" line is there to guide that choice.

The most common error is the age threshold. Younger children receive the child allowance instead and are left out of this credit, and because the threshold is rising each year, counting by last year's rule gives the wrong number. The next is both spouses claiming the same child. The credit goes to whoever lists the child as a basic-deduction dependant, and one child cannot be split between two parents.

Counting birth order by the number of qualifying children is another slip. First, second and third refer to the order of birth, so a newborn who is the third child earns ₩700,000 even if the older siblings are below the age threshold. A separate transitional clause excludes children born in 2017 from the phase-in and needs interpretation, so if you have a child born that year, check the provision itself. Finally, a tax credit cannot exceed the computed tax, so if other credits have already brought your tax to zero, the child credit does nothing.