Even if your wage income was already settled at year-end, if you also have business income (side jobs, freelance work), rental income, or other income exceeding KRW 3 million a year, you must recombine everything — including your wage income — and refile the comprehensive income tax in May. The wage tax already settled counts as tax already paid, so there's no double taxation.
Combining income often pushes you into a higher progressive bracket, resulting in additional tax owed, so if you have side income it's worth estimating the extra tax in advance.
Income types you must combine
Under KRW 3 million in other income? You get to choose
If occasional, non-recurring other income is KRW 3 million a year or less (after allowed expenses), you can choose between separate taxation (settled by withholding alone) or combining it into the comprehensive return — whichever is more favorable. If your other income already sits in a high bracket, separate taxation is often the better choice.
Frequently Asked Questions
Related Topics
Who Must File a Global Income Tax Return, How, and By When
Whether you need to file, how to do it on Hometax, and the May filing deadline (with its exceptions).
Income Tax Refunds and the Current Rate Table
Korea's 8-bracket progressive income tax table for 2026, and how to check and receive your refund.