How the Czechia paušální daň calculator is verified
Inputs
| Input | Field | Type |
|---|---|---|
| Annual revenue (CZK) | annualRevenue | 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) |
|---|---|---|
| Flat payment / month | monthlyPayment | annualRevenue <= $const.band1Limit ? $const.band1Monthly : (annualRevenue <= $const.band2Limit ? $const.band2Monthly : $const.band3Monthly) |
| Flat payment / year | annualPayment | $round(monthlyPayment * 12, 2) |
| Net income / year | netIncome | $round($max([0, annualRevenue - annualPayment]), 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 |
|---|---|
band1Limit | 1000000 |
band2Limit | 1500000 |
band1Monthly | 9984 |
band2Monthly | 16745 |
band3Monthly | 27139 |
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 — 900,000 CZK revenue — band 1
given annualRevenue | 900000 |
|---|---|
expect monthlyPayment | 9984 |
expect annualPayment | 119808 |
expect netIncome | 780192 |
Case 2 — 1,400,000 CZK revenue — band 2
given annualRevenue | 1400000 |
|---|---|
expect monthlyPayment | 16745 |
expect annualPayment | 200940 |
expect netIncome | 1199060 |
Case 3 — 1,800,000 CZK revenue — band 3, the top of the regime
given annualRevenue | 1800000 |
|---|---|
expect monthlyPayment | 27139 |
expect annualPayment | 325668 |
expect netIncome | 1474332 |
Sources
- Finanční správa — Paušální daň 2026: novinky, termíny a částky · checked 2026-08-22
- Pásma paušální daně 2026 — limity příjmů a měsíční částky (9 984 / 16 745 / 27 139 Kč) · 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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