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Calculate 19 tools
VAT calculatorAdd VAT to a price or extract it from a total.Profit marginCompare profit, margin and markup.Break-even revenueHow many sales cover your fixed costs?Loan repaymentMonthly payments and a complete repayment schedule.Margin scheme VATVAT on the positive margin of an eligible used item.DepreciationBook value, residual value and annual depreciation.Investment deductionSmall-scale investment deduction for 2026.Income taxFrom sole trader profit to income tax, healthcare contribution and net income.Provisional tax assessmentHow much remains to reserve for income tax and healthcare contribution?Freelance hourly rateA rate covering your net income, costs and tax.Gross to net salaryNet salary and holiday pay using payroll tax tables.Employer costsGross salary plus holiday allowance and employer contributions.Sole trader or limited companyCompare net income, tax and retained profits.Director salary and dividendCalculate salary, corporate tax and dividend in one overview.Holiday payGross holiday allowance and an estimated net payment.Minimum wageMinimum hourly wage and minimum pay for hours worked.Company car taxTaxable company car benefit and estimated net effect.Private or business carCompare annual car costs as a sole trader.Statutory interest and collection costsInterest by period and collection cost calculation.
Create 8 tools
Create invoiceEnter the details and download your PDF document.Create credit noteEnter the details and download your PDF document.Create quoteEnter the details and download your PDF document.Payment reminderCreate a reminder for an unpaid invoice.TimesheetRecord time by date and project, with totals and export.Mileage logTrips, odometer readings and business mileage in one export.Cash bookCash receipts, payments and running balance.SEPA payment fileCreate an XML file for euro transfers within the EEA.
Check 8 tools
XAF CheckerCheck auditfiles for balances, dates, VAT and references.Check UBL invoiceInvoice data, lines, VAT and totals from UBL XML.Check invoice amountsCheck entered invoice amounts, VAT and duplicate invoice numbers.Check IBANCheck country code, length and checksum.Check VAT numberCheck the format of a European VAT number.Normalise bank CSVConvert a bank export to consistent columns and dates.Check trial balanceCheck debit/credit, duplicate accounts and balance differences.Check payroll calculationCompare a regular payslip with the 2026 calculation table.
For entrepreneurs and advisers
A good conversation starts with clear figures.
Keep your scenarios, take a documented report with you or give clients a calculator on your website. Rekenbox works alongside your current bookkeeping.
Rekenbox · 2026
Payment reminder
Create a reminder for an unpaid invoice.Useful to know
How to use this tool
- Enter your own figures. The initial values are examples.
- Review the result, breakdown and any findings. Adjust your inputs to check again.
- Use the available free exports or view a report preview. Pro lets you save calculations and compare versions.
Which information do you need?
- Your business name
- Your address
- Your IBAN
- Customer name
- Customer address
- Original invoice number
- Original invoice date
- Reminder date
- New payment date
- Outstanding amount including VAT
- Personal note
Assumptions and scope
- A friendly payment reminder, not a new invoice, notice of default or statutory fourteen-day notice.
Year: 2026 · Version 2026.1
Sources for this tool
- Belastingdienst — factuureisen · checked 2026-09-04