How the Austria motorsteuer calculator is verified

Inputs

InputFieldType
Leistung (kW)kwnumber
CO₂ (g/km)co2number

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 valueFieldFormula (JSONata)
Pro Monatmonthly($k := kw - $const.kwFree; $k := $k > $const.minKw ? $k : $const.minKw; $c := co2 - $const.co2Free; $c := $c > $const.minCo2 ? $c : $const.minCo2; $round(($k + $c) * $const.rate, 2))
Pro Jahrannual$round(monthly * 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.

ConstantValue
kwFree62
co2Free106
rate0.72
minKw5
minCo25

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 — C1 85 kW, 120 g/km — 2026 Abzugswerte

given kw85
given co2120
expect monthly26.64
expect annual319.68

Case 2 — C2 147 kW, 180 g/km

given kw147
given co2180
expect monthly114.48
expect annual1373.76

Case 3 — C3 kleines E-freundliches Auto — die Mindestwerte von 5 greifen

given kw60
given co295
expect monthly7.2
expect annual86.4

Sources

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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