What is a GST invoice?

A GST invoice is a tax invoice issued by a GST-registered business in India for the supply of taxable goods or services. Under the CGST Rules, Rule 46, every sale or service supplied by a registered business must be accompanied by a GST invoice that contains specific mandatory fields.

CGST + SGST vs IGST — which do I charge?

Indian GST is split between Central and State governments. The split depends on whether the transaction is intra-state (supplier and buyer in the same state) or inter-state (different states):

• Intra-state (same state): charge CGST + SGST, split equally. If the GST rate is 18%, that's 9% CGST + 9% SGST.
• Inter-state (different states): charge IGST at the full rate. If the GST rate is 18%, that's 18% IGST.

The InsiteChat GST Invoice Generator detects intra-state vs inter-state automatically from the seller and buyer state you select, and applies the correct tax split.

India GST rates

India has five main GST rate slabs: 0% (exempt), 5%, 12%, 18%, and 28%. The rate depends on the HSN code (for goods) or SAC code (for services) of the item. Most professional services fall under 18%.

Mandatory fields on a GST invoice

1. Name, address, and GSTIN of the supplier
2. Consecutive invoice number and date of issue
3. Name, address, and GSTIN of the recipient (if registered)
4. HSN (goods) or SAC (services) code for each line item
5. Description, quantity, unit, rate, and taxable value of each line item
6. GST rate applied and CGST+SGST or IGST amounts
7. Place of supply and the recipient's state
8. Total invoice value in figures and words
9. Signature of the supplier or authorised representative

This generator includes all of the above. For e-invoicing (mandatory if your annual turnover crosses ₹5 Cr) you will additionally need to register the invoice on the IRP portal — that step is outside the scope of this free tool.