GST and invoicing
What is a tax invoice under GST? Format and rules
Definition
Tax invoice: A tax invoice is the bill a GST-registered business issues for a taxable sale, showing the buyer, items, values and GST in the form Rule 46 sets out.
Also called: GST invoice, GST bill, GST tax invoice, B2B invoice
What a tax invoice is
A tax invoice is the document a GST-registered seller issues for a taxable sale. It records what was sold, its value and the GST charged, and it is the document a registered buyer needs to claim input tax credit. For goods, section 31 of the CGST Act says the invoice must be issued before or at the time the goods are removed for delivery, not days later.
A business under the composition scheme, or one selling only exempt goods, issues a bill of supply instead and does not charge GST on it.
What a GST tax invoice must contain
Rule 46 of the CGST Rules lists the details. The ones every small business needs are:
- Your name, address and GSTIN.
- A consecutive invoice number of up to 16 characters, using letters, numbers, hyphens or slashes, unique for the financial year.
- The date of issue.
- The buyer's name, address and GSTIN if registered. For an unregistered buyer, the name, delivery address and state are needed when the taxable value is ₹50,000 or more.
- HSN code, description, quantity and unit of each item.
- Taxable value after discount, the GST rate and the tax amount as CGST and SGST or IGST.
- Place of supply with the state name for inter-state sales, and the delivery address if it is different.
- Whether tax is payable on reverse charge, and a signature or digital signature.
Copies, numbering and common mistakes
For goods, Rule 48 asks for three copies, marked Original for recipient, Duplicate for transporter and Triplicate for supplier. Services need two. Many businesses start a new number series each financial year, such as INV/26-27/0001.
The usual mistakes are gaps or repeats in the number series, numbers longer than 16 characters, a missing buyer GSTIN on a B2B sale, and CGST and SGST charged where IGST was due. If your aggregate turnover has crossed ₹5 crore in any year since 2017-18, B2B invoices must also go through the e-invoice system.
Worked example
A tax invoice in numbers
Invoice INV/26-27/00412, dated 14 October 2026, from a Rajkot snack maker to a distributor in Ahmedabad, both with GSTINs starting 24 (Gujarat). The distributor buys 40 cartons at ₹1,200 each, so the taxable value is ₹48,000. The place of supply is Gujarat (24), the same state as the seller, so at a 5% rate the invoice shows CGST at 2.5%, ₹1,200, and SGST at 2.5%, ₹1,200. The total is ₹50,400, written in words as Rupees fifty thousand four hundred only.
In managemate
In managemate, every counter sale and delivered sales order gets a consecutively numbered invoice from one series with your own prefix (INV- by default), and an invoice's number and date are final once issued. With your GSTIN set, it prints as a Tax invoice with your GSTIN and state, the buyer's GSTIN, place of supply, HSN codes, taxable value, CGST and SGST or IGST, a GST summary by rate, the amount in words and an Authorised signatory line. A4 order invoices print as Original for recipient, Duplicate for transporter or Triplicate for supplier. You set the prefix, next number and digits in Settings, so keep them within 16 characters. The invoice has no reverse charge line, so add one to your terms and conditions in Settings if your accountant wants it, and managemate does not issue bills of supply for composition businesses.
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