GST invoice rules
A GST tax invoice must carry set details about you, your buyer, the goods or services and the tax charged. Issue a credit note or debit note to change an invoice after it is sent, not an edit.
Last reviewed 2026-10-18. GST facts checked as of 2026-07-22.
What a tax invoice carries
- Your name, address and GSTIN.
- A consecutive serial number, unique for the financial year and no longer than the length shown below, and the date.
- Your buyer’s name, address and GSTIN, when the buyer is registered.
- A description of each item, with its HSN or SAC code, quantity and unit.
- The taxable value, with any discount shown.
- The tax rate and the tax amount, split into CGST and SGST or into IGST.
- The place of supply, with the state name, for a sale to another state.
- Whether tax is payable on reverse charge.
- Your signature or digital signature. A signature is not needed on an electronic invoice.
- For a sale to an unregistered buyer at or above the value shown below, the buyer’s name and address and the delivery address with its state.
Some invoices need more, for example a registered business above the e-invoicing limit must also print an IRN and a QR code. Check the current rules on the portal.
Other documents you may issue
- A bill of supply, in place of a tax invoice, when you sell exempt goods or services, or when you are under the composition scheme.
- A credit note, when you reduce the value or tax of an invoice you already issued, for example after a return or a discount. A credit note corrects a sale in a later document; it does not change the original invoice. GSTR-1 has separate tables for amendments.
- A debit note, when you increase the value or tax of an invoice.
- A delivery challan, when goods move without a sale.
Credit notes and debit notes are reported in your return, so each one should name the invoice it changes.
Correcting an invoice you sent
Do not edit a sent invoice. Issue a credit note for the difference, and a fresh invoice if needed, so your records and your return still match what your buyer holds.
Figures from the official source
- Longest invoice number:16 charactersas of 2026-10-18 · CGST Rules, 2017, rule 46(b)
- Unregistered buyer, details needed from a sale of:₹50,000 or moreas of 2026-10-18 · CGST Rules, 2017, rule 46(e)
How Bahi Khata helps
Bahi Khata makes a tax invoice with the right tax split, CGST and SGST inside your state and IGST to another state, and corrects a sent invoice with a credit note instead of editing it.
Official sources
Related guides
Questions
What must a GST invoice contain?
Your details, the invoice number and date, your buyer’s details, the items with codes, the taxable value, and the tax split into CGST and SGST or IGST.
How do I correct an invoice I already sent?
Issue a credit note for the difference, and a new invoice if needed.
When do I issue a bill of supply instead?
For exempt goods or services, and when you are under the composition scheme.
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