Official data
Tax bands, credits and entrepreneur rules come from Dutch Tax Administration publications; vehicle and inspection data comes from RDW. A secondary summary is never used as the source of a published rate.
ZZP calculation order
The calculator moves from revenue excluding VAT to business expenses and profit. It then applies entrepreneur deductions, the SME profit exemption, Box 1, tax credits and the income-related Zvw contribution. Employment credit uses profit before entrepreneur deductions and the SME exemption.
Starters and losses
The ordinary self-employed deduction is limited by profit. With the starter deduction, total deductions may exceed profit and create a tax loss. The calculator displays that loss but does not offset it against other income or other years.
Salary and BV
The salary tool is an annual model for a person below AOW age and excludes contract-specific pension and collective-agreement deductions. The BV comparison separates director salary, Zvw, corporation tax and Box 2, using the chosen payout percentage and separate administration costs. Salary is preserved in a loss year, and distributed dividends affect the general tax credit.
Boundary testing
After a rate change we test zero, negative input, values immediately below and above every band, the Zvw maximum, corporation-tax and Box 2 thresholds and every BPM emissions band. Published worked examples are recalculated too.
Deliberate limits
The site does not know your tax partner, mortgage, pension, other income, prior losses, benefits or complete payslip. Treat the result as a checkable estimate and obtain advice before filing or making a major structural or purchase decision.