Guide
GST invoice format
What an Indian tax invoice has to carry, why the tax splits in two on some invoices and not others, and how long you have to issue one.
A tax invoice under GST is not a free-form document. Rule 46 of the CGST Rules lists the particulars it has to carry, and an invoice missing one of them is a problem for your customer as much as for you — it is the document their input tax credit rests on.
The list below is what that comes to in practice. Nothing here is tax advice, and it does not replace your accountant; it is the format, so you can lay an invoice out correctly and get on with the work.
What has to be on it
Your name, address and GSTIN.
Unique, and consecutive within the financial year. Up to 16 characters — letters, digits, / and - only.
The date the invoice is raised.
Name, address, and GSTIN if they are registered. For an unregistered recipient above ₹50,000 you also need their address and the state.
The classification code for each good or service. How many digits depends on your turnover.
What was supplied, how much of it, and in what unit of measure.
The value per line after any discount, before tax is added.
Split into CGST and SGST, or shown as IGST — see below.
The state, which is what decides the split.
Whether tax is payable on a reverse-charge basis. State it either way.
Of the supplier or an authorised representative.
The CGST/SGST split, plainly
One rate, two ways of printing it. A sale where the place of supply is inside your own state is an intra-state supply: 18% GST is shown as 9% CGST plus 9% SGST. A sale where the place of supply is another state is inter-state: the same 18% is shown as one IGST line.
The customer pays the same total either way. Getting it wrong is the most common fault in a hand-made invoice, which is why the generator asks you one question — same state or another state — and prints the right lines from your answer.
Numbering
Invoice numbers must be unique and consecutive for the financial year, at most sixteen characters, using letters, digits, slashes and hyphens. A series like INV-202608-001 satisfies all of that and sorts correctly, which is the format the generator suggests and increments for you.
What it cannot do is know your other invoices. If you raise some through accounting software and some here, keep one series across both — a gap or a duplicate is the sort of thing that surfaces at exactly the wrong moment.
Copies
For goods, an invoice is issued in triplicate — original for the recipient, duplicate for the transporter, triplicate for you. For services it is in duplicate. A PDF you print twice satisfies this as well as pre-printed stationery does; the marking is what matters, and you can add it in the notes field.
Lay one out now
The generator puts every field above in its place, splits the tax the way you tell it to, and hands you the PDF. Free, no sign-up, and nothing you type leaves your browser.
Common questions
It depends on the place of supply, not on where you are. If the place of supply is in your own state, the rate splits in half — 18% becomes 9% CGST and 9% SGST. If it is in another state or a union territory, the whole 18% is a single IGST line. The customer pays the same amount either way; what changes is which government receives it.