GST Invoice Format: What It Must Contain (and a Free Template)
A GST tax invoice is valid only if it carries the fields Rule 46 of the CGST Rules lists, in particular a consecutive serial number, both parties' GSTIN, the HSN or SAC code, and the tax split. Get one of those wrong and your buyer's accountant will send it back, because their input tax credit depends on it.
What the law asks for
Rule 46 of the CGST Rules, 2017 sets out what a tax invoice must contain. The serial number must be consecutive and unique for the financial year, up to 16 characters, and may use letters, numbers, hyphens and slashes only. Place of supply decides the tax: within your own state it splits into CGST and SGST, across states it is a single IGST line. A registered supplier issuing a taxable supply must issue this invoice; a composition dealer issues a bill of supply instead, and must write that they cannot collect tax.
What the document must contain
- Invoice number and date (required): Consecutive, unique for the financial year, 16 characters maximum.
- Supplier name, address, GSTIN (required): Exactly as registered on the GST portal.
- Buyer name, address, GSTIN (required): GSTIN only if the buyer is registered.
- Place of supply (required): Decides CGST+SGST versus IGST. Mandatory on interstate supply.
- HSN or SAC code (required): Digits required depend on your turnover: 4, 6 or 8.
- Description, quantity, unit (required): Enough that the item is identifiable.
- Taxable value and discount (required): Discount shown before tax if it was agreed at or before supply.
- Tax rate and amount per tax (required): CGST, SGST, IGST and cess shown separately.
- Total in words (optional): Not required by law, but most buyers expect it.
- Reverse charge declaration (required): State whether tax is payable on reverse charge.
- Signature or digital signature (required): Of the supplier or an authorised person.
Frequently asked questions
Is there a fixed GST invoice format prescribed by the government?
No single design is prescribed. Rule 46 lists the particulars the invoice must contain; the layout is yours. Any template that carries all the required fields is valid.
How many digits of HSN code do I need?
It scales with turnover. Small suppliers use 4 digits, larger ones 6, and 8 digits are required for exports and certain notified goods. If your turnover crosses a slab mid-year, the higher requirement applies from the next financial year.
Can I issue a GST invoice in Excel?
Yes. Excel, Word or a printed book are all acceptable as long as the required particulars are present and the numbering stays consecutive. The risk with Excel is broken numbering and lost copies, not legality.
What is the difference between a tax invoice and a bill of supply?
A tax invoice is issued when GST is charged. A bill of supply is issued for exempt supplies or by a composition dealer, who cannot collect tax and must say so on the document.