How we calculate your take-home pay
Tax calculators are only useful if they are right. This page explains where our rules come from in every country, how we test them, and how to check our work.
How a rule gets onto this site
Every rate in every country goes through the same five steps before anyone sees a number based on it. Nothing is published until two independent checks agree.
- Read from the official source
Tax rates, thresholds and contribution rates come from each country’s own tax authority and official payroll specifications. We never copy commercial rate tables. Each number is stored with its source link and the date we read it.
- Checked again from a second source
A separate check re-reads every number from a different official document. Any mismatch stops the update.
- Tested against known answers
Each calculator must reproduce the official worked examples and our published test cases exactly, to the smallest unit of the currency.
- Cross-checked by a second calculator
An independent reference calculator, written separately, works out thousands of generated cases. The two must agree exactly before a release.
- Published with a version number
Each country’s rules have a version number, shown under every result and recorded in the changelog. Old versions never change.
Accuracy grades
Every country and calculator shows how closely it follows official payroll rules.
Every live country
Only countries that have passed their accuracy gate are listed. Each country’s methodology page shows its sources and every published test case.
Annual figures and your payslip
Our main result is your tax for the whole year. Payroll works one pay period at a time and rounds in its own way, so a payslip can differ by a little each period. Where a country publishes its payroll method, the calculator shows that calculation too. Bonuses, a change in your circumstances or starting mid-year can make bigger differences.