Free Invoice Tools

BTW calculator, invoice number generator, and payment due date calculator. No sign-up required. 100% free.

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BTW / VAT Calculator

Calculate VAT instantly for NL, UK, DE, BE

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Invoice Number Generator

Generate professional invoice numbers instantly

INV-5163

Best practices for invoice numbering:

  • ✓ Use sequential numbers so no gaps appear
  • ✓ Each invoice number must be unique
  • ✓ Include a prefix or year for easy filing
  • ✓ Never reuse a number, even for cancelled invoices
  • ✓ Required by Dutch (KVK) and EU tax law

Payment Due Date Calculator

Calculate when invoices are due

Due dateMonday, 27 April 2026
Status30 days remaining

Need more than a calculator?

Create professional invoices in 60 seconds. Auto payment reminders. Multi-country support.

Start Free - 20 Invoices/Month

No credit card required.