Free GST Invoice Format — What a Valid GST Tax Invoice Must Contain

A GST tax invoice is the document a GST-registered seller issues for a taxable supply of goods or services. It records that the supply happened, fixes the tax charged, and is what your buyer needs to claim input tax credit (ITC) — so getting the format right matters. Under Rule 46 of the CGST Rules, a tax invoice has a defined set of particulars: a consecutive serial number, the supplier's GSTIN (and the recipient's GSTIN where registered), HSN/SAC codes, taxable value, and the correct split of CGST and SGST/UTGST or IGST. This page explains exactly what a compliant GST invoice format includes and how to produce one. With KukBook you can create, print and share GST tax invoices for free, and for GST documents also generate your GSTR-1 and GSTR-3B return data, e-invoices (with IRN and QR code) and e-way bills from the same billing data — no re-keying.

What this GST tax invoice includes

Tips

Keep invoice numbers consecutive within each series for the financial year — gaps or duplicates are a common cause of GSTR-1 mismatches and ITC queries for your buyers.
Pick IGST vs CGST+SGST from the place of supply, not just the buyer's billing address — an intra-state vs inter-state error is among the most frequent GST invoicing mistakes.
Apply the correct HSN/SAC digit length for your turnover (4 digits up to Rs. 5 crore, 6 digits above, for B2B supplies) so your returns don't get flagged.
If your turnover crosses the e-invoicing threshold, generate the e-invoice (IRN + QR) before sending — for a notified taxpayer, a B2B invoice without a valid IRN is not a valid tax invoice.
Issue a credit or debit note rather than editing a finalised invoice, so your records and GSTR-1 stay consistent and auditable.

Frequently asked questions

What is the difference between a tax invoice and a bill of supply?

A tax invoice is issued for taxable supplies and shows the GST charged, which lets a registered buyer claim input tax credit. A bill of supply is issued when no GST is charged on the invoice — for example by a composition-scheme dealer or for exempt supplies — and carries no tax amount.

What fields are mandatory on a GST invoice?

Under Rule 46 of the CGST Rules a tax invoice must carry the supplier's name, address and GSTIN; a consecutive serial number; the date; the recipient's details and GSTIN (where registered); HSN/SAC codes; description, quantity and value of supply; the GST rate and amount split into CGST/SGST or IGST; the place of supply for inter-state sales; whether tax is payable on reverse charge; and the supplier's signature.

When do I charge IGST instead of CGST and SGST?

You charge IGST when the place of supply is in a different State or Union territory from the supplier (an inter-state supply). When the location of the supplier and the place of supply are in the same State, you split the tax into CGST and SGST/UTGST instead.

Can I create and share a GST invoice for free with KukBook?

Yes. KukBook lets you create, print and share GST tax invoices at no cost. For GST documents it also generates your GSTR-1 and GSTR-3B return data, e-invoices with IRN and QR code, and e-way bills from the same invoice data, so you don't have to re-enter anything.

Create your GST tax invoice free — print, share, and generate GSTR-1/3B, e-invoice and e-way bill from the same data. Start free for 90 days, no credit card.