Free invoice number generator
Under Rule 46 of the CGST Rules, a GST invoice number must be a consecutive serial number of up to 16 characters, unique for the financial year, using only letters, numbers, a hyphen or a slash. This tool builds a compliant series from a prefix, an optional branch code and the financial year, and warns you if it gets too long.
Learn more: GST invoice number rules · Invoice numbering best practices
- INV/26-27/0001 (14 chars)
- INV/26-27/0002 (14 chars)
- INV/26-27/0003 (14 chars)
✓ Within the 16-character limit and uses only allowed characters.
Runs entirely in your browser; nothing is sent or stored.
Invoice number generator: FAQ
How long can a GST invoice number be?
Rule 46(b) of the CGST Rules allows a consecutive serial number of not more than 16 characters, in one or multiple series, containing letters, numerals, hyphen or dash and slash, unique for a financial year.
Can I restart invoice numbers every year?
Yes. Numbers only need to be unique within a financial year, so most businesses restart at 1 on 1 April and include the year, such as INV/25-26/0001.
Can I run separate series for branches?
Yes. Multiple series are allowed, for example one per branch or per document type, as long as each number is unique for the year.