Individual Global Income Tax: When Do You Combine All Your Income?

- 11월 14, 2025

Part 18 of 20 · Individual Tax (Comprehensive Filing)

Individual Global Income Tax: When Do You Combine All Your Income?

Wages, business, interest, dividends—even “other income.” Learn when Korea requires you to aggregate them and file in May.

1) What is Global Income Tax?

Global (comprehensive) income tax is Korea’s system for taxing the sum of an individual’s annual earnings from multiple sources so ability-to-pay is measured on the whole picture.

2) Income types included (and excluded)

Included (6 types): Interest, Dividends, Business, Wages & Salaries, Pensions, Other Income.
Usually excluded (separate regimes): Retirement income, Capital gains (taxed under separate rules).

Wages are typically pre-paid via monthly withholding and reconciled at year-end (Ep.12–14), but still count toward global income if you must file.

3) Financial income rule: the KRW 20M test

Interest + dividends that were withheld at source (≈14%) are normally separately taxed and finished if the annual total ≤ KRW 20,000,000.

≤ KRW 20M: No aggregation required (separate taxation completes the liability).
> KRW 20M (or any non-withheld items): Must aggregate into global income and file.

Tip: Track bank interest + domestic/overseas dividends together—crossing KRW 20M flips you into comprehensive taxation.

4) Other income rule: the KRW 3M test

Other income (one-off prizes, license fees, lotteries, etc.) is generally withheld at 20%.

Per-type amount ≤ KRW 3,000,000: Usually remains under separate taxation.
Exceeds KRW 3,000,000: That type switches to global income and must be included on filing.

5) Progressive rates & brackets

Global income uses progressive national rates (plus local income tax at 10% of the national tax):

Tax base (KRW)	Rate	Progressive deduction
Up to 14,000,000	6%	-
… (intermediate brackets omitted for brevity)	…	…
Over 500,000,000	42%	35,940,000
Over 1,000,000,000	45%	65,940,000

Effective burden = national tax per brackets + 10% local income tax on that national amount.

6) Filing window & who must file

When: May 1–31 (following year). Certain compliant-filing subjects may file by June 30.
Must file if:
- You have business income (freelance/sole proprietor) beyond withholding scope;
- Your financial income exceeds KRW 20M (interest+dividends) or includes non-withheld items;
- Certain other income per type exceeds KRW 3M;
- Multiple wage sources requiring aggregation, or foreign-source income requiring report.

Quick decision rule: Business? File. Interest+dividends > KRW 20M? File. Big “other income”? File.

7) Common mistakes & quick checks

KRW 20M test 미확인: 금융소득 합산 누락으로 가산세 위험.
여러 급여지 합산 누락: 복수 근무, 이직 시 연말정산만 믿고 미신고.
해외 배당/이자 미신고: 국외원천 금융소득 빠뜨림.
기타소득 3M 룰 오해: 유형별 한도임을 간과.

Tip: 1) 이자·배당 전년 합계 확인, 2) 기타소득 유형별 금액 체크, 3) 복수 급여 원천징수영수증 취합.

8) Summary & next topic

Global income = wages, business, pensions, interest, dividends, other income combined.
Financial income ≤ KRW 20M stays separate; if > KRW 20M, you aggregate and file.
Other income per type ≤ KRW 3M stays separate; above that, aggregate and file.

Next (Part 19): Overseas Financial Accounts—who must report, thresholds, and penalties.

9) Disclaimer

General information only, not personal tax advice. Thresholds and rules can change; confirm current guidance or consult a professional.

Tags (hidden)

Global Income Tax Financial Income 20M Rule Other Income 3M Rule Interest and Dividends Comprehensive Filing Korean Taxation Series KRTaxPolicy

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