Invoice Numbering
Also called: invoice series, invoice number series
What is Invoice Numbering?
Invoice numbering is the consecutive series a business uses to identify its invoices. Under GST the series must be unique within a financial year and may run up to sixteen characters, with letters, digits, slashes and hyphens allowed.
Why Invoice Numbering matters
Gaps, duplicates and restarts are among the first things scrutiny looks for, because they suggest bills issued outside the books. A clean series is also what makes credit notes and payment matching traceable.
How Invoice Numbering works in practice
Generate numbers from one system rather than several notebooks. Separate series per outlet or document type are fine as long as each is internally sequential and identifiable, such as OUT1/25-26/0001.
Common mistakes with Invoice Numbering
- Restarting numbering mid-year after switching billing systems.
- Handwritten bills running in parallel with system-generated ones.
- Reusing a cancelled invoice number for a different sale.
Frequently asked questions
Yes, and it is the normal practice, provided the series is unique within that year.