A registered business that makes a taxable supply has to issue a tax invoice, and Rule 46 of the CGST Rules lists what it must show. Miss a detail and your buyer may not get input tax credit, or an officer may treat the bill as incomplete. Here is the full list in plain language.
When you must issue a tax invoice
- Goods: before or at the time the goods are removed or delivered to the buyer.
- Services: within 30 days of providing the service.
- Small retail sales: for a sale below ₹200 to an unregistered buyer who doesn't ask for an invoice, you may issue one consolidated invoice for all such sales at the end of the day.
If you are a composition dealer, or the goods are exempt, you issue a bill of supply instead. See bill of supply vs tax invoice.
The Rule 46 checklist
A tax invoice must show:
- Your name, address and GSTIN.
- An invoice number: consecutive, unique for the financial year and at most 16 characters (see below).
- The date of issue.
- The buyer's name, address and GSTIN, if the buyer is registered.
- For an unregistered buyer, when the taxable value is ₹50,000 or more: the buyer's name and address, the delivery address, and the state's name and code.
- The HSN code for goods or the SAC for services (how many digits depends on your turnover, see below).
- A description of the goods or services.
- Quantity and unit for goods (for example 2 Nos, 1.5 Kg).
- The total value of the supply.
- The taxable value, after any discount or abatement.
- The tax rate and amount, shown separately as CGST and SGST (or UTGST) for a sale within your state, or IGST for a sale to another state, plus cess if any.
- Place of supply with the state's name, for an inter-state supply.
- The delivery address, if it is different from the place of supply.
- Whether tax is payable on reverse charge. For an ordinary shop sale this is "No".
- Your signature or digital signature, or that of your authorised representative.
Invoice numbers
- At most 16 characters.
- Only letters, digits, the hyphen
-and the slash/. - Consecutive and unique within the financial year. Most shops start a fresh series every 1 April, such
as
INV/2026-27/0001. - You can run more than one series, for example one per counter or per branch, as long as each is consecutive. Every series you use is reported in GSTR-1's documents table.
How many HSN digits
This depends on your aggregate annual turnover in the previous financial year:
- Up to ₹5 crore: 4-digit HSN on invoices to registered buyers. Optional on invoices to unregistered buyers.
- Above ₹5 crore: 6-digit HSN on all invoices.
GSTR-1's HSN summary follows the same digit rule, so getting the codes right on the invoice saves work at filing time.
How many copies
- Goods: three copies, marked Original for Recipient, Duplicate for Transporter and Triplicate for Supplier.
- Services: two copies, Original for Recipient and Duplicate for Supplier.
When e-invoicing applies
If your aggregate turnover has crossed ₹5 crore in any financial year from 2017-18 onwards, invoices to registered buyers must also be reported to the Invoice Registration Portal (IRP). The portal returns an IRN and a QR code that must be printed on the invoice. Below that limit, a normal tax invoice like the one above is enough.
Mistakes that cause trouble
- Wrong or missing buyer GSTIN. The sale shows up as B2C in GSTR-1 and the buyer can't claim credit.
- CGST + SGST on a sale that should be IGST, or the other way round. The place of supply decides which, not where the buyer paid.
- Gaps or repeats in the invoice series, often from cancelled bills deleted instead of marked cancelled.
- Changing a product's price or GST rate and reprinting an old invoice with the new figures. An issued invoice must stay exactly as issued. Corrections go through a credit or debit note.
How InvenCore handles it
InvenCore prints the title Tax Invoice (or Bill of Supply for composition dealers) with:
- your business details and GSTIN
- a numbered invoice series per financial year
- buyer and ship-to details with GSTIN
- HSN/SAC on every line
- the CGST + SGST or IGST split, worked out from your GSTIN and the buyer's state
- an authorised signature image
- the three copies for goods
Past invoices never change when you edit a product later. InvenCore doesn't generate e-invoice IRNs, so it suits shops below the e-invoicing limit.
This guide is general information, not tax or legal advice. GST rules change through notifications and circulars, so check the latest position on gst.gov.in and cbic-gst.gov.in, or ask your tax professional.