How the Luxembourg salaire net calculator is verified
Inputs
| Input | Field | Type |
|---|---|---|
| Salaire brut annuel (EUR) | 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) |
|---|---|---|
| Cotisations (~12,45%) | contrib | $round(grossAnnual * $const.contribRate, 2) |
| Base imposable | taxable | $round(grossAnnual - contrib, 2) |
| Impôt (classe 1, + fonds pour l emploi) | tax | ($t := taxable; $g := (($t > 13230 ? (($t < 25000 ? $t : 25000) - 13230) : 0) * 0.15) + (($t > 25000 ? (($t < 45000 ? $t : 45000) - 25000) : 0) * 0.25) + (($t > 45000 ? (($t < 100000 ? $t : 100000) - 45000) : 0) * 0.35) + (($t > 100000 ? ($t - 100000) : 0) * 0.42); $round($g * 1.07, 2)) |
| Net / an | netAnnual | $round(grossAnnual - contrib - tax, 2) |
| Net / mois | 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 |
|---|---|
contribRate | 0.1245 |
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 EUR class 1
given grossAnnual | 50000 |
|---|---|
expect contrib | 6225 |
expect taxable | 43775 |
Case 2 — S3 120,000 EUR class 1
given grossAnnual | 120000 |
|---|---|
expect contrib | 14940 |
expect taxable | 105060 |
Sources
- Impôts directs (barème) · checked 2026-08-02
- CCSS cotisations · 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.
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