A GST-registered business in India can't just add a tax line to a regular invoice template and call it compliant — a few specific details are expected, and one formatting choice in particular (how the tax itself is broken down) trips people up regularly.
What a GST invoice needs beyond the basics
- GSTIN — the seller's GST registration number should appear on the invoice, and the buyer's too if they're also GST-registered (needed for them to claim input tax credit).
- HSN/SAC codes — a classification code identifying the specific good or service being sold, used for tax reporting purposes.
- The applicable GST rate — shown explicitly, not folded silently into the total.
- Place of supply — relevant for determining whether the transaction is intra-state or inter-state, which affects the next point.
CGST + SGST, or a single combined rate?
This is the detail that catches people off guard: for a transaction within the same state, GST is split into two equal halves — CGST (Central GST) and SGST (State GST) — each shown as its own line at half the total rate. An 18% intra-state transaction shows as 9% CGST plus 9% SGST, not a single 18% line. For a transaction across state lines, it's shown differently again, as a single IGST (Integrated GST) line at the full rate instead. Which format applies depends on where the seller and buyer are located relative to each other, not on the tax rate itself.
Why this matters beyond just formatting
This isn't cosmetic — the split reflects how the tax is actually allocated between central and state governments, and a GST-registered buyer relies on the invoice showing it correctly to claim their own input tax credit properly. An invoice with the wrong breakdown can create real reconciliation problems for the buyer's own GST filing, not just look slightly off.
Using the tool
Our Invoice Generator includes a GST split option — turn it on and the tax line automatically divides into CGST and SGST at half the entered rate each, formatted the way an intra-state GST invoice expects, instead of a single combined tax line.
Try it here: Invoice Generator. You may also want our GST Calculator to work out inclusive/exclusive amounts before you build the invoice, and our GSTIN Validator to double-check a registration number.