GST Invoice Format India — A Practical Guide for Freelancers

The 11 mandatory fields

• Supplier name, address and GSTIN
• Recipient name, address and GSTIN (if registered)
• Sequential invoice number unique per financial year
• Date of issue
• HSN / SAC code per line item
• Description, quantity, unit, rate, amount
• Taxable value (after discount, before tax)
• CGST + SGST or IGST rate and amount
• Total invoice value (figures and words)
• Place of supply (especially inter-state)
• Signature of supplier or authorised representative

CGST + SGST vs IGST — pick by place of supply

If your supplier and customer are in the same state, you charge CGST + SGST (each typically 9%, totalling 18%).

If they are in different states, you charge a single IGST (18% in our example). Same total, different label.

Tip: Use 'IGST' on the invoice for inter-state supplies — it's the cleanest format and the GST portal accepts it directly.

HSN / SAC codes — keep them inside line items

Add the HSN (goods) or SAC (services) code right inside the description, e.g.:

• Web development services — SAC 998314

For invoices over ₹5 crore aggregate annual turnover, HSN is mandatory at 6 digits. Below that, 2–4 digits is fine.

Service exports = zero-rated

If you bill an overseas client (say, USD invoices to a US client), it qualifies as a zero-rated export of services under Section 16 of the IGST Act.

On the invoice, set GST to 0 and add this line in Notes:

• "Zero-rated supply under LUT — IGST 0% — Export of services"

Don't forget to file your LUT (Letter of Undertaking) annually on the GST portal — without it, you'd have to charge IGST and claim it back as a refund.