Tools that know the Dutch rules.
23 calculators and generators built on the actual regulations: the elfproef, the 8% vakantiegeld rule, the transitievergoeding formula, the AOW table, movable public holidays. Not a generic percentage calculator with a Dutch label.
Why a separate set for the Netherlands.
Most of the work these tools do is not arithmetic, it is knowing the rule. A severance payment is not a flat percentage, it follows a formula tied to years of service. A BSN is not a random number, it has to survive the elfproef. Ascension Day moves every year. An AOW age is fixed for one group and merely expected for another.
Every tool below encodes the rule as it actually reads, states its source, and is explicit about where an estimate ends and an official determination begins.
Work and income
Dutch employment rules are specific: notice periods follow years of service, holiday allowance is a fixed percentage, and severance has its own formula. These tools apply the actual rules rather than a generic percentage.
Money and tax
VAT rates, mortgage capacity, and state pension dates all follow Dutch rules that change on their own schedule.
Dates and planning
Dutch public holidays include movable feasts and King's Day rules that generic calendars get wrong.
Education
Dutch grading and school transition rules have their own conventions.
Test data for Dutch systems
Software that validates Dutch identity and payment data needs test data that passes the same checks without belonging to a real person. See the dedicated test data page for the full set.
For developers and AI agents.
Several of these rules are available as endpoints, so your own software does not have to reimplement them: BTW calculation, VAT number format checks, Dutch public holidays, working days, and the test data generators. Free API key, and the same tools work inside AI assistants through the MCP server.