Trust
How We Calculate Your Take-Home Pay — Sources & Methodology
Our data sources, annual update process and the deliberate simplifications behind every estimate on FinAdministrator.
6 min read · Reviewed May 2026
Static, sourced, versioned data
Every figure in our calculators comes from versioned, officially-sourced data files — not a live API. We record the source URL and retrieval date for each country and tax year, and we archive old years rather than deleting them, so prior-year pages stay accurate.
This means calculations run entirely in your browser, with nothing you type sent anywhere, and every number is traceable back to an official government publication.
What we calculate — and simplify
For each salary we apply the country's income tax (band by band), its mandatory social or payroll contributions, and any region-specific rules you select. We're explicit about simplifications: some sub-national figures (US state rates, certain regional taxes) are estimates we're still verifying, and we flag them in the calculator.
These are close estimates for a typical employee, not a payslip. They can't capture every personal allowance, benefit-in-kind or local levy.
Updated every year
Tax law changes by statute annually, so we publish a new data file each tax year and re-verify every figure against its official source before the new year's calculators go live. Our methodology page lists the sources for each country.
If you ever spot an error, tell us — accuracy is the entire point of a tax tool, and we'd rather fix it fast.
Related
Frequently Asked Questions
+How accurate are FinAdministrator's calculations?
They use official current-year tax brackets and contribution rates, sourced and dated on our methodology page, and are accurate estimates for a typical employee. They can't capture every personal circumstance, so confirm before making decisions.
+Does FinAdministrator store my salary?
No. All calculations run locally in your browser against static data files. Nothing you enter into a calculator is transmitted or stored — we only process data for the newsletter, contact form and paid report.
Estimate only — not tax advice. Figures are estimates based on publicly available tax rules and may not reflect your full circumstances. See our methodology & sources (last reviewed June 2026). Always confirm with an official tax authority or a licensed adviser before making decisions.