If you have a side gig alongside a job, work as a freelancer, or earn rental or financial income in Korea, you file comprehensive income tax in May. "Am I on the hook? How much will it be?" Here's the 2026 rate table, filing steps, and tax-saving points in one place.
What it is
It combines your various income streams and taxes the total. If you only have one job and finished year-end settlement, you usually don't file. But the following income triggers a May filing.
| Included income | Examples |
|---|---|
| Business | Self-employed, income tax calculator, platform work |
| Employment | Two or more salaries combined |
| Interest/dividends | Combined if over 20M won/yr |
| Rental | dependent deductions |
| Other/pension | Other income, certain private pensions |
2026 rate table
Tax applies to your tax base (income minus deductions) as base × rate − progressive deduction.
| Tax base | Rate | Deduction |
|---|---|---|
| ≤ 14M won | 6% | – |
| 14M – 50M | 15% | 1.26M |
| 50M – 88M | 24% | 5.76M |
| 88M – 150M | 35% | 15.44M |
| 150M – 300M | 38% | 19.94M |
| 300M – 500M | 40% | 25.94M |
| 500M – 1B | 42% | 35.94M |
| Over 1B | 45% | 65.94M |
Rates are progressive — only the portion above each bracket is taxed at the higher rate, so your effective rate is lower than your marginal one. Same idea as US tax brackets.
Example: 60M won base
A freelancer with a 60M-won tax base falls in the 24% bracket: 60M × 24% − 5.76M = 8.64M won. Subtract taxes already withheld (the 3.3%) to see whether you owe more or get a income tax calculator.
Key deductions
| Deduction | Detail |
|---|---|
| Business expenses | Ledger or expense-rate basis |
| Personal | Self and dependents |
| Pension account credit | Pension savings / IRP |
| Noran Umbrella | Small-business owner deduction |
| Medical/education/donations | If criteria met |
Income deductions cut the tax base; tax credits cut the tax itself. Use both.
How and when to file
- Window — May 1–31 (June for honest-filing taxpayers).
- How — Hometax / mobile Sontax e-filing; a "pre-filled" notice makes it simple.
- Local income tax — an extra 10% of the income tax.
Missing the deadline brings a 20% non-filing penalty; if you're owed a refund, you simply don't get it. See the tax calendar.
FAQ
I have a job and a small side income — file?
Generally yes, if you have business or other income beyond salary. See unclaimed refunds.
I'm a freelancer taxed 3.3% — pay again?
The 3.3% is prepaid tax. You settle in May and often get a refund.
Is my whole income taxed at 24%?
No — only the portion above the bracket (progressive). The deduction reflects that.
Two filings, not one
Comprehensive income tax and local income tax are separate filings to separate bodies — the tax office and your local authority. In practice Hometax hands you off: after you submit the national return, a “go to local income tax” button carries the figures over to Wetax. People who close the browser at the first confirmation screen often miss the second half and hear about it later. Seoul also runs staffed filing desks in every district office through the May window, which is worth knowing if the online forms defeat you in Korean.
Sources and where to check
- Seoul Metropolitan Government — notice on filing local and comprehensive income tax (May 2026). For 2025 income the deadline moved to 1 June because 31 May fell on a Sunday.
- Seoul Metropolitan Government — how to file comprehensive income tax. Confirms the six income types, the 30 June deadline for certified filers, and the 20% penalty for not filing.
- Seoul Labor Rights Center — how employees and freelancers file differently. Anyone paid with 3.3% withheld must file the following May.
Written as of July 2026. Deadlines and penalties come from the Seoul city and Seoul Labor Rights Center pages above. One caveat: the progressive-deduction figures in the rate table and the 10% local income tax could not be checked against a public-agency page — the National Tax Service site was unreachable. Verify those on Hometax. This is general information, not tax advice. See also the VAT guide and the tax calendar.
