How to create an invoice number
Every invoice should have a unique invoice number so you and your client can match payments and track records. Use a simple sequence (1001, 1002, …) or a format that includes the year or client code.
Best practices: (1) Use numbers only or a short prefix (e.g., INV-1001, 2026-001). (2) Assign numbers in order; don’t skip or reuse. (3) Keep a log or use your accounting software so you know the next number. (4) Put the invoice number clearly on the invoice (see invoice format).
You don’t need special software to create an invoice number—just pick a starting number and increment. Our invoice generator and invoice templates include a field for the invoice number; you fill it in when you create each invoice. For a full guide, see how to create invoices and how to write an invoice.