How we Calculate
The same method runs behind all twenty calculators on this site. Only the rates change. This page explains the arithmetic, what every field does, what we leave out, and when you should ignore our number and speak to somebody.
The arithmetic
Gross pay goes in. Take home pay comes out. In between, the calculator walks the same eight steps every time, in this order, because tax systems apply their rules in a fixed sequence and changing the order changes the answer.
- Convert gross pay to an annual amount.
- Subtract the pension contribution.
- Subtract social contributions that reduce taxable income.
- Subtract the tax-free allowance and standard deductions.
- Apply the income tax bands progressively to the remainder.
- Subtract tax credits from the calculated tax.
- Calculate the remaining employee contributions on gross salary.
- Subtract every deduction from gross pay to give take home pay.
Step five does the work people usually get wrong. Bands are progressive nearly everywhere, so a higher rate applies only to the slice of income above its threshold, not to the whole salary. Moving into a higher band doesn’t cut your take home pay.
Steps three and seven are separate on purpose. Some social contributions come off before income tax is worked out; others are charged on gross salary and don’t reduce your taxable income at all. Bundling them together is the most common source of a wrong answer.
What each field does
Every calculator on this site shares these fields. Each country adds its own on top, and those are explained on the country’s own page.
Gross (pre-tax) income
Your full pay before any tax or contributions come off.
Every figure in the result is derived from this. Enter it yearly, monthly or weekly and we’ll convert it for you.
Tax year
The tax year the calculation should use.
Rates and thresholds are set per tax year. The year decides which rules apply. Several countries don’t run their tax year to the calendar, which is why the label sometimes reads across two years.
Filing status
Whether you’re assessed on your own or jointly with a spouse or civil partner.
In most systems this changes the bands or reliefs you’re entitled to. The same salary can produce a different result. In a few it changes nothing at all.
How old are you?
Your age band, not your exact age.
Age affects contribution rules and age-related reliefs in many countries.
Pension contributions
What you pay into a pension, as a percentage or a fixed amount.
Pension contributions reduce the income you’re taxed on. Leaving them out overstates your tax.
Other allowances and deductions (advanced)
An annual amount to add to your tax-free allowance.
Covers country-specific reliefs the main form doesn’t model yet.
Exclude social contributions (advanced)
Turns the country’s main employee contribution off so you can see income tax on its own.
Useful when you’re comparing headline income tax rates between countries. Every country bundles social contributions differently.
What we assume about you
A calculator that asked every question would take twenty minutes to fill in. We’ve fixed these instead, and each country page repeats the list with its own local wording:
- Employment is a standard contract, not self-employment;
- Residence is in the country for the full tax year;
- Regional and municipal income taxes carry the national average rate where they apply;
- Dependants and family tax credits stay outside the calculation unless a field collects them;
- Employer contributions stay outside take home pay because employers pay them;
- Pay spreads evenly across the year rather than per payroll period.
The last one matters more than it looks. Cumulative payroll systems settle up across the year, so a single month’s payslip can differ from one twelfth of our annual figure and still be correct.
When this is the wrong tool
Every calculator here models one situation: an employee, tax-resident for the full year, paid a salary. That covers most people. It doesn’t cover everyone, and the further you sit from that description, the more our number drifts from your payslip.
Don’t rely on it if:
- You’re self-employed, a contractor, or paid through your own company. Contribution rates and the deductions available to you are different, and our figure will usually be too generous.
- You arrived or left partway through the tax year. Most systems apportion allowances by the months you were resident, and we assume a full year.
- A large part of your pay is bonus, equity, commission or benefits in kind. Several countries tax these on separate rules from salary.
- You claim reliefs the form doesn’t collect, such as dependants, disability, or a regional exemption. Those move the answer, sometimes a long way.
In any of those cases, treat our figure as a rough upper bound and check with an accountant or your national tax authority.
Where the rates come from
Every rate, band and threshold on this site is taken from the country’s own tax authority, never from a secondary source and never from another calculator. Each country page names its authority and links to the page the figures came from.
Each country’s rules live in their own file, with the source and the date it was last checked recorded alongside. When a country publishes new rates, we update that file and the date on the country page moves with it. If the date on a page looks stale to you, it is; tell us and we’ll re-check.
This site gives guidance, not financial advice. We advise you to consult a specialist regarding any major financial decisions.