GST
Allowed characters and length of invoice number
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Facts
Rule 46(b) allows only letters, numbers, hyphen (-) and slash (/), with a maximum of 16 characters. Spaces, underscores and other symbols are not allowed.
Provisions and law
- Rule 46(b), CGST Rules 2017Serial number in one or more series using letters, numbers, hyphen and slash, up to 16 characters, unique for the financial year
Analysis
A number like DL_2026 001 breaks the rule twice. Use DL-2026-001 instead. E-invoice systems and GSTR-1 uploads reject invalid characters, so fixing the format early saves errors.
Conclusion
- Review your invoice format.
- Remove spaces and special characters other than - and /.
- Keep the total at 16 characters or fewer.
- Test one upload to GSTR-1 or the IRP.
A Savvy can do this for you
Invoice series, numbering and document summary (GSTR-1 Table 13)
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