Methodology
How we calculate and verify Dutch tax estimates
Belastbaar calculators are designed to be transparent, year-aware, and easy to audit. This page explains how we use tax data, calculation logic, sources, and review checks.
Centralized tax dataOfficial-source checksEditorial review
Tax year coverage
Calculator pages use the current 2026 rules from the centralized tax data set unless a user selects another supported year.
Editorial review
Calculator content and explanations are reviewed by the Belastbaar editorial team.
Estimates, not assessments
Calculator outputs are educational estimates and do not replace personal tax advice or a final Dutch Tax Administration assessment.
Centralized tax data
- Tax brackets, credits, deductions, thresholds, and calculator constants are stored in the shared tax-data layer.
- Year-specific values live in versioned tax-year files, so calculator pages can follow the selected tax year consistently.
- Calculator pages should not hardcode tax constants; they should read from the shared data source.
Calculation logic
- Calculators use pure tax-calculation functions where practical, with UI components passing inputs into reusable calculation modules.
- The tax scan and results surfaces reuse the same shared state and tax-engine patterns so values stay consistent across flows.
- For complex or edge-case rules, we keep the explanation visible and treat the result as an estimate.
Sources and verification
- Primary references include Dutch Tax Administration publications, official government information, and the centralized Belastbaar tax data set.
- When tax-year data changes, calculator copy and examples should be checked against the shared data source rather than updated manually in one page.
- We prioritize clear, source-backed calculations over black-box estimates.
Update cadence
- Tax-year data is updated when official rules, thresholds, or calculator assumptions change.
- Pages are reviewed when calculator logic changes, when new tax-year data is added, or when source material is updated.
- Known limitations and assumptions should remain visible where they materially affect a user's result.
Important note: Belastbaar provides educational tax information. Personal circumstances, exemptions, and edge-case rules can change the outcome. For binding advice, consult a qualified tax advisor or the Dutch Tax Administration.