South Korea self-employed net income calculator (개인사업자)
Your net income as a Korean sole proprietor is business income minus global income tax across eight bands after the basic deduction, plus local income tax charged at a flat 10% of the national tax itself.
Worked example: with Annual business income after expenses of 60,000,000, this model computes Net income / year 50,892,000. See the full breakdown.
⚠ Illustrative rates Updated for 2026 · sources checked 2026-08-22
How 개인사업자 in South Korea is calculated
The Korean local income tax is not a second rate on income — it is 10% of the national tax. That distinction is why every headline band understates the real burden by exactly a tenth: a 35% bracket is an effective 38.5%, and a 45% bracket is 49.5%. It is collected with the same return and rarely mentioned separately.
The other Korean particularity is on the expense side. A sole proprietor below certain prior-year revenue thresholds may use a statutory simplified expense rate (단순경비율) set by business code instead of documenting costs, which for some trades is far more generous than real expenses would be. Which method you may use is decided by your business code and last year’s revenue, not by choice.
Worked example
| Annual business income after expenses (KRW) | 60000000 |
|---|---|
| Taxable Income ✓ | 58500000 |
| National income tax ✓ | 8280000 |
| Local income tax (10% of it) ✓ | 828000 |
| Net income / year ✓ | 50892000 |
Every row is computed by the engine from the inputs above. Rows marked ✓ are additionally pinned by a published self-test vector.
Frequently asked questions
How much tax on 60,000,000 KRW of business income?
About 8,280,000 KRW of national income tax plus 828,000 KRW of local income tax, leaving roughly 50,892,000 KRW before national pension and health insurance.
What is the local income tax?
A flat 10% of the national income tax, not of income. It makes every band effectively 1.1 times the published rate.
Does this include national pension and health insurance?
No. Both are compulsory and substantial for a sole proprietor and are not deducted here, so your real net income is lower than the figure shown.
Sources
- 국세청 — 종합소득세 세율 · checked 2026-08-22
- 2026년 종합소득세 세율·과세표준 및 지방소득세 10% · checked 2026-08-22
Estimate. Not tax advice. The rates in this calculator are illustrative: they reproduce the shape of the charge through 3 self-test cases, but they are not the official schedule, so the amount shown will not match your bill. Use the official source above for that.
Check the arithmetic yourself: how this calculator is verified — the formula behind every derived value, the 3 test cases the engine reproduces, and what the badge does and does not claim. Also available as machine-readable JSON.
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