GST invoice format: mandatory fields and how to make one for free

Rule 46 of the CGST Rules lists the details a tax invoice must carry. The main ones:

• Supplier's name, address and GSTIN.
• A consecutive serial number, unique for the financial year, of up to 16 characters (letters, numbers, - and /).
• Date of issue.
• Buyer's name, address and GSTIN if registered. For an unregistered buyer, their name, address and state when the taxable value is ₹50,000 or more.
• HSN code for goods or SAC code for services, a description, quantity and unit.
• Total value, taxable value after discounts, tax rate and tax amount for each of CGST, SGST/UTGST, IGST and cess.
• Place of supply with the state name for inter-state supplies, and the delivery address if different.
• Whether tax is payable on reverse charge.
• Signature or digital signature of the supplier or an authorised person.

1. 1Open GST invoice and enter your business details. GSTINs are checked as you type, and your details are remembered on this device for next time.
2. 2Enter the buyer's details. The place of supply decides whether the tool applies CGST + SGST or IGST.
3. 3Add each item with its HSN or SAC code, quantity, rate and GST rate.
4. 4Check the totals and the amount in words, then download the PDF.
5. 5Sign it with Sign PDF if you don't use a digital signature.

Businesses with an aggregate turnover of up to ₹5 crore in the previous year must show at least 4-digit HSN codes on invoices to registered buyers; above ₹5 crore, 6 digits are required on all invoices.

If your turnover makes e-invoicing mandatory for you, each B2B invoice must also be registered on the Invoice Registration Portal to get an IRN and QR code. This tool creates the invoice document; the IRN still has to come from the portal.