May is South Korea’s annual filing and payment period for comprehensive income tax. Individuals with comprehensive income in 2025 must file and pay from May 1 to June 1, 2026.
Comprehensive income tax combines interest, dividends, business income, wages, pensions and other income. Even salaried workers may need to file if they also earned side income such as freelance pay, financial income or rental income.
Those who may need to file include workers who received wages from two or more employers last year but did not complete a combined year-end tax settlement, employees who left a job midyear and did not complete year-end settlement, and the self-employed and freelancers with business income. Other income such as one-time lecture fees or manuscript fees must be reported if the annual amount exceeds 3 million won.
Financial income can also trigger a filing requirement. If annual financial income, including interest and dividends, exceeds 20 million won, a comprehensive income tax return is required. Private pension income may require a choice between comprehensive taxation and separate taxation depending on whether it exceeds 15 million won a year.
In general, people with only wage income who completed year-end settlement through their employer do not have to file. Also excluded are insurance solicitors, door-to-door salespeople and contract delivery sellers whose prior-year revenue was under 75 million won and who have no other income, if their affiliated company completed year-end settlement. Taxpayers with only retirement income and business income subject to year-end settlement, only tax-exempt or separately taxed income, or other income of 3 million won or less who choose separate taxation also are not required to file a final return.
Returns can be filed through the National Tax Service’s Hometax website or its mobile app, Sontax. During the May filing period, Hometax provides a dedicated filing screen and, after login, guides users to a tailored process based on their filing type.
For taxpayers eligible for the agency’s pre-filled “Modu Chaeum” service, the process is simpler. They can review the pre-calculated tax due or refund based on income data held by the tax agency and submit the return. Eligible taxpayers can also file by phone through an automated response system, and the agency provides instructions for phone filing with its notices.
If tax is due after filing, payment can be made through Hometax or Sontax by bank transfer, credit card or simple payment services. Taxpayers can also transfer to a designated virtual account or print a payment slip and pay at a financial institution.
Failing to file or pay by the deadline may result in penalties, including for nonfiling and late payment. The National Tax Service said taxpayers must file on time if they have income subject to reporting, even if they did not receive a filing notice.
The comprehensive income tax return is used to settle multiple types of income earned in the previous year. Taxpayers with income beyond wages — including midyear job changes, side work, financial income or rental income — should confirm whether they must file during the May period.
* This article has been translated by AI.
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