Invoice number generator
Build a correct, sequential invoice number and see the next in the series. Gap-free, the way tax authorities expect.
Your next numbers
- INV-2026-0001
- INV-2026-0002
- INV-2026-0003
- INV-2026-0004
- INV-2026-0005
- INV-2026-0006
How to number invoices correctly
Invoice numbers must be sequential and unique, with no gaps — HMRC in the UK and the EU VAT rules both require it, so a missing number looks like a hidden invoice. A common, safe format is a short prefix, the year, and a zero-padded counter (INV-2026-0001), reset yearly or run continuously. Pick a format once and keep to it.