Indian businesses registered under GST must issue invoices that comply with the GST Act. Correct tax splitting between intra-state (CGST+SGST) and inter-state (IGST) transactions is critical for input tax credit.
Master the GST invoice format: 15-digit GSTIN, HSN/SAC codes, proper tax rate application, CGST/SGST/IGST split calculations, and e-invoicing requirements for businesses above the turnover threshold.
Under India's GST regime, every registered business must issue a tax invoice that includes the 15-digit GSTIN of both the supplier and the recipient. The GSTIN is not optional: invoices without valid GSTINs cannot be used by the recipient to claim input tax credit, which is the cornerstone of the GST system. The HSN code for goods (or SAC code for services) must also appear on every invoice. Businesses with annual turnover above 5 crore rupees must use 6-digit HSN codes, while those below that threshold can use 4-digit codes. The tax split between CGST and SGST (for intra-state sales) or IGST (for inter-state sales) must be calculated and displayed separately on the invoice. A common mistake is applying CGST plus SGST to an inter-state transaction, which results in an incorrect tax amount and a rejected invoice. The GST portal provides a tool to verify GSTINs, and we recommend checking every new buyer's GSTIN before issuing the first invoice.