A GST invoice is not just a receipt — it is the document your customer needs to claim input tax credit, and the record a tax officer checks first. Miss a mandatory field and the invoice can be treated as invalid. Here is what the rules actually require.
Mandatory fields on a tax invoice
- Supplier name, address and GSTIN
- A consecutive serial number (max 16 characters), unique for the financial year
- Date of issue
- Customer name, address, and GSTIN if registered (B2B)
- For unregistered customers where the value exceeds ₹50,000 — name, address, and state with code
- HSN code for goods or SAC for services (digit count depends on turnover)
- Description, quantity, unit, total value
- Taxable value after discount
- Rate and amount of CGST, SGST/UTGST, IGST and cess shown separately
- Place of supply for inter-state sales
- Whether tax is on reverse charge
- Signature or digital signature of the supplier
Tax invoice vs bill of supply
Registered regular dealers issue a tax invoice. A composition dealer, or anyone supplying exempt goods, issues a bill of supply — no tax is shown, and a composition dealer must print “composition taxable person, not eligible to collect tax on supplies”.
When to issue it
For goods: on or before delivery or removal. For services: within 30 days of supply. For continuous supply: on or before the due date of each payment.
B2C billing at a shop counter
Below ₹200, a registered person need not issue an invoice unless the customer asks — but most POS systems issue one anyway for stock and reporting. A consolidated daily invoice can cover the small B2C sales.
Related
What is GST e-invoicing? · How to choose billing software
FAQ
How many digits of HSN code do I need on my invoice?
Businesses with turnover up to ₹5 crore use 4 digits for B2B (optional for B2C); above ₹5 crore use 6 digits. E-invoices require at least 6.
Can I revise an invoice serial number series each year?
Yes. The series must be consecutive and unique within a financial year. Many businesses restart numbering each April with a year prefix.