How the France Salaire net (net salary) calculator is verified
Inputs
| Input | Field | Type |
|---|---|---|
| Salaire brut annuel | grossAnnual | number |
| Parts fiscales | parts | 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) |
|---|---|---|
| CSG + CRDS | csgCrds | $round(grossAnnual * $const.csgCrdsBase * $const.csgCrdsRate, 2) |
| Cotisations retraite | socialOther | $round(grossAnnual * $const.socialRate, 2) |
| Total Contrib | totalContrib | $round(csgCrds + socialOther, 2) |
| Net avant impôt / an | netAvantImpot | $round(grossAnnual - totalContrib, 2) |
| Taxable IR | taxableIR | $round(netAvantImpot * (1 - $const.abatement), 2) |
| Impôt sur le revenu | incomeTax | ($q := taxableIR / parts; $t := $q <= 11600 ? 0 : $q <= 29579 ? ($q - 11600) * 0.11 : $q <= 84577 ? ($q - 29579) * 0.30 + 1977.69 : $q <= 181917 ? ($q - 84577) * 0.41 + 18477.09 : ($q - 181917) * 0.45 + 58386.49; $round($t * parts, 2)) |
| Net après impôt / an | netApresImpot | $round(netAvantImpot - incomeTax, 2) |
| Net Monthly | netMonthly | $round(netApresImpot / 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 |
|---|---|
csgCrdsRate | 0.097 |
csgCrdsBase | 0.9825 |
socialRate | 0.1131 |
abatement | 0.1 |
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 30,000 EUR non-cadre single (1 part)
given grossAnnual | 30000 |
|---|---|
given parts | 1 |
expect csgCrds | 2859.08 |
expect socialOther | 3393 |
expect totalContrib | 6252.08 |
expect netAvantImpot | 23747.92 |
expect taxableIR | 21373.13 |
expect incomeTax | 1075.04 |
Case 2 — S2 45,000 EUR married with 2 children (3 parts) — quotient lowers tax
given grossAnnual | 45000 |
|---|---|
given parts | 3 |
expect csgCrds | 4288.61 |
expect socialOther | 5089.5 |
Sources
- Barème IR — impots.gouv.fr · checked 2026-08-02
- Barème de l'impôt sur le revenu (loi de finances pour 2026) — service-public.gouv.fr · checked 2026-10-17
- Taux de cotisations — Urssaf · checked 2026-10-17
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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