Invoice Number Generator
Generate sequential invoice numbers with custom prefix and padding. Download as CSV.
Sequential Invoice Numbers: Why Consistency Matters
Invoice numbering is not just about organisation — under GST in India, invoice numbers must be sequential within a financial year, unique and not exceed 16 characters. The GST portal cross-references invoice numbers between buyers and sellers for ITC reconciliation. A consistent, professional numbering format (INV-2024-001) also makes it easier to track payment status, follow up on overdue invoices and pass audits.
Frequently Asked Questions
What is the correct format for invoice numbers under GST? ▼
The format is flexible but must be: unique within a financial year, sequential (not necessarily consecutive), maximum 16 characters, no special characters except hyphens and slashes. Common formats: INV/2024-25/001, RC-2024-001, FIRM/FY24/INV/001. Reset the sequence at the start of each financial year (April 1).
Can I reuse invoice numbers in a new financial year? ▼
Yes — invoice sequences reset every financial year (April 1). INV-2024-001 in FY 2024-25 and INV-2024-001 in FY 2025-26 are different invoices. Include the financial year in your invoice number format to avoid confusion: INV/FY25/001.
What happens if invoice numbers are not sequential? ▼
Non-sequential invoice numbers can attract GST audit scrutiny — auditors may suspect missing invoices (to evade tax). Always maintain sequential numbering. If an invoice is cancelled, mark it as CANCELLED (do not reuse the number) and note the cancellation in your books.
How to number invoices for multiple clients? ▼
Two approaches: (1) Single sequence across all clients: INV-001, INV-002, INV-003... (simplest, most common). (2) Client-specific sequence: CLIENTNAME-001, CLIENTNAME-002... (useful for large businesses with dedicated client accounts). Our generator supports custom prefixes for approach 2.