Free GST Invoice Generator — Auto CGST/SGST/IGST Calculation
Indian businesses need GST-compliant invoices for every sale above the threshold — and getting them right matters. A wrong tax type, missing HSN code, or miscalculated CGST/SGST split can cause GSTR mismatch and ITC denial for your client. Our free GST invoice generator handles all of this automatically: it picks CGST + SGST when seller and buyer are in the same state, and IGST when they're in different states. No signup, no software install, no errors.
What every GST invoice must contain
Per Rule 46 of CGST Rules, a GST tax invoice must include: invoice number and date, seller's name + GSTIN + address, buyer's name + GSTIN + address (if registered), HSN/SAC code, description, quantity, rate, taxable value, GST rate and amount split (CGST/SGST/UTGST/IGST), place of supply, total invoice value, and signature. Our generator includes every one of these fields by default — including amount in words in Indian lakh/crore format.
How CGST, SGST and IGST work
- Intra-state sale (seller and buyer in the same state): GST is split equally between CGST (Centre) and SGST (State). Example: an 18% rate becomes 9% CGST + 9% SGST.
- Inter-state sale (different states): the full GST is charged as IGST and later distributed by the Centre.
- UTGST applies in Union Territories without a legislature.
The tool decides this for you the moment you set "Place of Supply".
Works for every state
Whether you are a trader, manufacturer, wholesaler, exporter or service business, the tool handles every state pair correctly, including special-rate Union Territories. Whether you raise 5 invoices a month or 500, you can generate them in seconds.
HSN code basics
HSN (Harmonised System of Nomenclature) codes classify goods; SAC (Service Accounting Code) classifies services. Businesses with turnover under ₹5 crore must use 4-digit codes; above ₹5 crore, 6-digit codes are mandatory. Always include them on the invoice — the GSTN portal validates them at filing time.
From manual invoicing to automated GST billing
Generating invoices one at a time is fine when you're starting out, but at scale you'll want automation: auto-numbering, customer database, recurring invoices, e-invoice (IRN/QR) generation, and direct upload to GSTN. We build custom GST billing portals integrated with your website — see our cost calculator for typical pricing, or take our app quiz if you're considering a billing app for your sales team. Not a GST seller? Use our free freelancer invoice generator instead.