What is a GST invoice?
A GST invoice is the tax document for taxable supplies under GST. It carries GSTIN, HSN/SAC, value, and tax — and enables the buyer’s ITC claim.
A GST invoice is a legal tax document issued under Section 31 of the CGST Act for every taxable supply of goods or services. It records the supplier and buyer's GSTIN, the HSN or SAC code, the taxable value, and the tax amount charged — and it is what allows a registered buyer to claim input tax credit on that purchase.
Without a valid GST invoice, that input tax credit simply cannot be claimed, even if payment was made.
What a GST invoice must show
Exact formats can vary, but a compliant invoice usually includes:
- Supplier name, address, and GSTIN
- Buyer name, address, and GSTIN (for B2B)
- Unique invoice number and date
- Description of goods or services
- HSN (goods) or SAC (services) code
- Quantity and unit (for goods)
- Taxable value
- Rate and amount of CGST/SGST or IGST
- Place of supply where required
- Signature or digital equivalent as applicable
Missing key fields can cause problems for your buyer’s ITC and for your own filings.
GST invoice vs bill of supply
Use a GST tax invoice when you charge GST on a taxable supply.
Use a bill of supply when you do not charge GST — for example under composition scheme or for exempt supplies (as per applicable rules). A bill of supply does not create ITC for the buyer in the same way a tax invoice does.
When to issue it
For goods, invoice timing often ties to removal or delivery. For services, it usually ties to supply or payment rules under GST. Issue invoices promptly and keep serial numbers continuous so books stay easy to audit.
Example
You sell ₹10,000 of taxable goods at 18% IGST to a registered buyer in another state. Your GST invoice shows taxable value ₹10,000 and IGST ₹1,800, with both GSTINs and the HSN. The buyer uses that invoice (once reflected in returns) to claim ITC of ₹1,800, subject to eligibility.
Creating GST invoices without manual errors
Handwritten or spreadsheet invoices often miss HSN, tax split, or GSTIN format. Billing software fills those fields from saved products and parties.
Billoxy generates GST-compliant invoices so the bills you issue are structured for your customer’s ITC claim and for your GSTR reporting.
To make one GST invoice now, use the GST invoice generator.
For GST billing software, see Billoxy.