How the South Korea take-home pay calculator is verified
Inputs
| Input | Field | Type |
|---|---|---|
| 연봉 (KRW) | grossAnnual | number |
The formula
Each derived value below is computed by the Valem engine from the expression shown, in this order. Nothing else runs — there is no hidden code path.
| Derived value | Field | Formula (JSONata) |
|---|---|---|
| 4대 보험 (~9.4%) | social | $round(grossAnnual * $const.socialRate, 2) |
| Taxable | taxable | ($b := grossAnnual - social - $const.deduction; $round($b > 0 ? $b : 0, 2)) |
| 소득세 | nationalTax | ($t := taxable; $round((($t < 14000000 ? $t : 14000000) * 0.06) + (($t > 14000000 ? (($t < 50000000 ? $t : 50000000) - 14000000) : 0) * 0.15) + (($t > 50000000 ? (($t < 88000000 ? $t : 88000000) - 50000000) : 0) * 0.24) + (($t > 88000000 ? (($t < 150000000 ? $t : 150000000) - 88000000) : 0) * 0.35) + (($t > 150000000 ? ($t - 150000000) : 0) * 0.38), 2)) |
| 지방소득세 (10%) | localTax | $round(nationalTax * 0.10, 2) |
| 연 실수령 | netAnnual | $round(grossAnnual - social - nationalTax - localTax, 2) |
| 월 실수령 | netMonthly | $round(netAnnual / 12, 2) |
Rates and thresholds
The expressions above read these as $const. They are the figures the annual refresh replaces, so they live as data rather than being written into the formulas — which is what makes a year-on-year change a one-line diff instead of an edit to arithmetic.
| Constant | Value |
|---|---|
socialRate | 0.0971 |
deduction | 8000000 |
Test vectors (2)
Every case is executed against this model on each build, by the Java engine and independently by a JavaScript one. A mismatch of a single cent fails the build, so the page cannot ship advertising a figure the model no longer produces.
Case 1 — S1 50,000,000 KRW
given grossAnnual | 50000000 |
|---|---|
expect social | 4855000 |
Case 2 — S2 80,000,000 KRW
given grossAnnual | 80000000 |
|---|---|
expect social | 7768000 |
Sources
- 국세청/Hometax · checked 2026-08-02
Check it yourself — and reuse it
The whole model as JSON — inputs, outputs, formulas, vectors and sources in one re-runnable document.
This model is published under CC BY 4.0: use it, adapt it, build on it, with attribution. The licence covers the model — the expression of each rule and the arrangement of the catalog. The rates and thresholds are law, and nobody licenses those; the sources above are where they come from.
← Back to the South Korea take-home pay calculator
Built with Valem — a live, verifiable calculator you can fork and embed.