GST invoice format

What is a GST tax invoice?

A GST tax invoice is the primary legal document issued by a registered GST taxpayer when selling goods or services. It is the basis for the buyer to claim Input Tax Credit (ITC) and for the seller to discharge their GST liability. Every GST-registered business must issue a valid tax invoice for every taxable supply.

Mandatory fields on a GST invoice

Under Rule 46 of the CGST Rules, a tax invoice must include:

• Supplier details: name, address and GSTIN
• Consecutive invoice number (unique for the financial year) and date
• Buyer details: name, billing address, state and GSTIN (for B2B)
• Place of supply (determines CGST+SGST vs. IGST)
• HSN/SAC code for each line item
• Description of goods or services, quantity and unit
• Taxable value per line (after any discount)
• GST rate and amount: CGST + SGST (intra-state) or IGST (inter-state)
• Total invoice value in words and figures
• Signature of the authorised signatory

CGST, SGST vs. IGST — which applies?

If the supplier and buyer are in the same state, the GST is split into CGST (central) and SGST (state), each at half the slab rate. If they are in different states, the full rate goes as IGST. Use the GST calculator to compute the exact amounts.

GST invoice format preview

The table below shows the standard column structure of a GST tax invoice line-item section:

When to issue a GST invoice

For goods, issue the invoice at or before delivery. For services, issue within 30 days of service completion (45 days for banking/financial institutions). Late invoices attract interest under the CGST Act. Use a GST invoice generator to create and date invoices instantly.

Related resources

• GST rates & slabs guide — which slab applies to your goods
• HSN code finder — look up the correct HSN/SAC code
• Best GST billing software 2026 — automate invoicing end-to-end