Invoice Numbering
Invoice numbering is the sequential, unique numbering system a business must follow for its invoices under GST rules — typically a consecutive series, unique per financial year.
Under GST rules, invoices must be numbered in a consecutive series that is unique for each financial year — you can’t skip numbers arbitrarily or reuse a number, and the series should be clearly identifiable (e.g. a prefix plus a running number).
A common approach freelancers use is a format like INV-2026-001, INV-2026-002, and so on, resetting the running number (but not necessarily the prefix) at the start of each financial year.
Gaps or duplicates in your invoice numbering are one of the first things flagged in a GST audit, so many invoicing tools enforce numbering automatically rather than leaving it to be typed in manually each time.
Written by the InvoicePilot Team.