How to Make a GST Invoice: Format, Mandatory Fields and a Free Template

6 min read · GST

A GST invoice is not just a bill — it's the document that lets your customer claim input tax credit and that your GSTR-1 is built from. Get the fields or the tax split wrong and it fails at both ends. Here is exactly what a valid tax invoice needs.

Mandatory fields on a GST tax invoice

Every tax invoice must show: your name, address and GSTIN; a consecutive invoice number (unique for the financial year) and the date; the customer's name, address and GSTIN (for B2B); the HSN or SAC code of each item; the taxable value; the GST rate and amount split into CGST/SGST or IGST; the place of supply; and the total. A signature (or digital signature) completes it.

CGST/SGST vs IGST — the split that trips people up

When the supplier and the place of supply are in the same state, GST splits into CGST + SGST (half each). When they're in different states, a single IGST applies at the full rate. So an 18% item shows 9% + 9% within a state, or 18% IGST across states. The place of supply — not where the buyer's office is — decides it.

How many HSN digits do you need?

Turnover up to ₹5 crore: 4 digits on B2B invoices. Above ₹5 crore: 6 digits. The HSN also fixes the rate, so the code and the rate must agree.

Bill of supply, revised and credit/debit notes

A composition dealer or an exempt supply uses a bill of supply (no tax shown), not a tax invoice. Corrections after issue go through credit or debit notes under section 34 — you don't edit the original. Keeping the numbering consecutive and gap-free is what makes GSTR-1 reconcile.

General information, not tax advice. Rules change — confirm the current requirements with your CA.