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Invoicing5 Jan 2026 · 5 min read

GST Invoice Rules in India: What Every Invoice Must Contain

A GST invoice isn't just a bill — it's a legal document that determines whether your buyer can claim input tax credit. Missing fields can invalidate it. Here's exactly what a compliant tax invoice must contain.

Mandatory fields on a GST invoice

  • Your business name, address, and GSTIN.
  • A unique, sequential invoice number and the invoice date.
  • Customer name, address, and GSTIN (for B2B).
  • HSN code for goods or SAC code for services.
  • Description, quantity, unit, and taxable value of each item.
  • The GST rate and the tax amount split into CGST + SGST (same state) or IGST (inter-state).
  • Place of supply, especially for inter-state sales.
  • Total invoice value in figures.

CGST/SGST vs IGST — the split

For a sale within your own state, the tax splits equally into CGST (central) and SGST (state). For a sale to another state, the whole tax applies as IGST. Getting this wrong is one of the most common invoicing errors — the total is the same, but the split must match the place of supply.

Never worry about the fields again

BizGST Pro builds every mandatory field into each invoice automatically — the correct tax split based on state, HSN codes from your item master, and sequential numbering. You fill in the customer and items; the compliance is handled.

Stay GST-compliant without the hassle

BizGST Pro creates compliant invoices with the correct tax split automatically, tracks payments, and keeps your GSTR-1 ready. Free forever to start.

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