Guide · 9 min read

GST invoice format: what every invoice must show

A GST tax invoice has to include specific details for your customer to claim input tax credit. Here's the checklist, in plain English, plus how to create compliant invoices without a spreadsheet.

Updated 12 October 2026 · By the SuperForge team

01Mandatory fields on a GST tax invoice

Rule 46 of the CGST Rules lists what a tax invoice must contain. In summary:

  1. Supplier's name, address and GSTIN.
  2. A consecutive invoice number, unique for the financial year, up to 16 characters (letters, numbers, hyphen or slash).
  3. Date of issue.
  4. Recipient's name, address and GSTIN (if registered).
  5. Name and address of the recipient, and the state name and code, if the recipient is unregistered and the value is ₹50,000 or more.
  6. HSN code for goods or SAC code for services.
  7. Description of the goods or services.
  8. Quantity and unit (for goods).
  9. Total value, and the taxable value after any discount.
  10. Tax rate and amount: CGST and SGST/UTGST, or IGST, plus any cess.
  11. Place of supply, with the state name, for inter-state supplies.
  12. Delivery address, if different from the place of supply.
  13. Whether tax is payable on reverse charge.
  14. Signature or digital signature of the supplier or an authorised person.

02CGST + SGST or IGST?

SaleTax chargedExample at 18%
Within the same state (intra-state)CGST + SGST (or UTGST)9% CGST + 9% SGST
To another state (inter-state)IGST18% IGST

The place of supply decides which applies. Good invoicing software works this out from the supplier's and buyer's states.

03HSN and SAC codes

Businesses with aggregate turnover up to ₹5 crore in the previous year must show at least 4-digit HSN codes on B2B invoices; above ₹5 crore, 6 digits. Services use SAC codes. Rules change, so confirm the current requirement with your CA.

04Invoice numbering

Numbers must be consecutive and unique within a financial year. Gaps raise questions in an audit, which is why software that issues numbers only when an invoice is finalised (gapless numbering) is safer than typing them by hand.

05E-invoicing

Businesses above the e-invoicing turnover threshold (₹5 crore at the time of writing) must report B2B invoices to the Invoice Registration Portal and print the IRN and QR code. Check the current threshold on the GST portal.

06Create GST invoices in minutes

SuperForge's Commerce Forge fills in your GSTIN, calculates CGST/SGST or IGST from the place of supply, adds HSN/SAC codes from your product list, numbers invoices without gaps and prints a UPI QR so customers can pay instantly.

07Questions

What is the format of a GST invoice?

A GST tax invoice must show the supplier's and recipient's details and GSTIN, a unique consecutive invoice number, date, HSN/SAC codes, description, quantity, taxable value, tax rates and amounts (CGST/SGST or IGST), place of supply and a signature.

How many characters can a GST invoice number have?

Up to 16 characters, using letters, numbers, hyphens or slashes, unique for the financial year.

When do I charge IGST instead of CGST and SGST?

Charge IGST on inter-state supplies. Charge CGST plus SGST (or UTGST) when the supplier and place of supply are in the same state.

This guide is general information, not tax advice. GST rules change; confirm details with your chartered accountant or the GST portal.

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