How the Ireland sole trader calculator is verified
Inputs
| Input | Field | Type |
|---|---|---|
| Annual profit after expenses (EUR) | annualProfit | 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 | ($p := annualProfit; $round($max([0, $const.lowRate * $min([$p, $const.standardBand]) + $const.highRate * $max([0, $p - $const.standardBand]) - $const.taxCredits]), 2)) |
| USC | usc | ($p := annualProfit; $round($p <= $const.uscExemption ? 0 : $const.uscR1 * $min([$p, $const.uscB1]) + $const.uscR2 * $max([0, $min([$p, $const.uscB2]) - $const.uscB1]) + $const.uscR3 * $max([0, $min([$p, $const.uscB3]) - $const.uscB2]) + $const.uscR4 * $max([0, $p - $const.uscB3]), 2)) |
| Class S PRSI | prsi | $round(annualProfit < $const.prsiFloor ? 0 : $max([$const.prsiMinimum, annualProfit * $const.prsiRate]), 2) |
| Net income / year | netIncome | $round($max([0, annualProfit - incomeTax - usc - prsi]), 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 |
lowRate | 0.2 |
highRate | 0.4 |
taxCredits | 3750 |
uscB1 | 12012 |
uscB2 | 28700 |
uscB3 | 70044 |
uscR1 | 0.005 |
uscR2 | 0.02 |
uscR3 | 0.03 |
uscR4 | 0.08 |
uscExemption | 13000 |
prsiRate | 0.042375 |
prsiMinimum | 650 |
prsiFloor | 5000 |
Test vectors (3)
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 — 60,000 EUR profit — a typical full-time sole trader
given annualProfit | 60000 |
|---|---|
expect incomeTax | 11450 |
expect usc | 1332.82 |
expect prsi | 2542.5 |
expect netIncome | 44674.68 |
Case 2 — 25,000 EUR — part-time, standard rate only
given annualProfit | 25000 |
|---|---|
expect incomeTax | 1250 |
expect usc | 319.82 |
expect prsi | 1059.38 |
expect netIncome | 22370.8 |
Case 3 — 120,000 EUR — into the top USC band
given annualProfit | 120000 |
|---|---|
expect incomeTax | 35450 |
expect usc | 5630.62 |
expect prsi | 5085 |
expect netIncome | 73834.38 |
Sources
- Revenue — Universal Social Charge (USC) rates and PRSI for the self-employed · checked 2026-08-22
- Budget 2026 Ireland — tax rates, bands, USC and PRSI · checked 2026-08-22
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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