How the Ireland take-home pay calculator is verified
Inputs
| Input | Field | Type |
|---|---|---|
| Gross annual salary (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) |
|---|---|---|
| Income tax (after credits) | incomeTax | ($t := grossAnnual; $g := ($t < $const.standardBand ? $t : $const.standardBand) * 0.20 + ($t > $const.standardBand ? ($t - $const.standardBand) : 0) * 0.40; $x := $g - $const.credits; $round($x > 0 ? $x : 0, 2)) |
| USC | usc | ($t := grossAnnual; $round((($t < 12012 ? $t : 12012) * 0.005) + (($t > 12012 ? (($t < 28700 ? $t : 28700) - 12012) : 0) * 0.02) + (($t > 28700 ? (($t < 70044 ? $t : 70044) - 28700) : 0) * 0.03) + (($t > 70044 ? ($t - 70044) : 0) * 0.08), 2)) |
| PRSI | prsi | $round(grossAnnual * $const.prsiRate, 2) |
| Net / year | netAnnual | $round(grossAnnual - incomeTax - usc - prsi, 2) |
| Net / month | 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 |
|---|---|
standardBand | 44000 |
credits | 4000 |
prsiRate | 0.042 |
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 40,000 EUR single
given grossAnnual | 40000 |
|---|---|
expect incomeTax | 4000 |
expect usc | 732.82 |
expect prsi | 1680 |
expect netAnnual | 33587.18 |
Case 2 — S3 90,000 EUR single
given grossAnnual | 90000 |
|---|---|
expect incomeTax | 23200 |
expect prsi | 3780 |
Sources
- Revenue — tax rates & credits · 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 Ireland take-home pay calculator
Built with Valem — a live, verifiable calculator you can fork and embed.