What a GST-compliant invoice must contain in India

If you are registered under GST, your invoices are not just payment requests — they are tax documents. An invoice missing required fields can be rejected by your client, and it complicates your own filing.

The fields every GST invoice needs

• Your business name, address, and GSTIN
• A unique, sequential invoice number and the date of issue
• The client name, address, and their GSTIN if they are registered
• A description of the goods or services, with HSN or SAC codes
• Taxable value, the rate applied, and the tax amount
• The place of supply, which determines how the tax splits
• Total payable, and a signature or digital equivalent

CGST and SGST, or IGST

The split depends on where your client is. If the place of supply is in your own state, the tax divides into CGST and SGST — 9% and 9% for an 18% rate. If your client is in another state, it is a single IGST line at the full 18%. Getting this wrong is one of the most common errors on freelance invoices, and it is worth checking on every invoice rather than assuming.

Sequential numbering matters more than people expect

Invoice numbers must be unique and sequential within a financial year. Gaps and duplicates draw attention during scrutiny, and reconstructing a clean series afterwards is far more painful than getting it right from the start. Let your invoicing tool assign the number rather than typing it by hand.

None of this is legal advice — thresholds and rules change, and your specific situation may differ. If you are unsure whether you need to register, or which rate applies to your services, a chartered accountant is worth the consultation fee.