GST Invoice Format — Every Field, and What It Is For

The fields a tax invoice carries

The list below is the full set for a tax invoice on a taxable sale of goods. Not every field applies to every sale — a buyer without a GSTIN has no GSTIN to print, and a seller not registered for GST raises a different kind of document entirely.

• Invoice number, unique within the business, and the invoice date
• Seller's name, address and GSTIN
• Buyer's name, address and GSTIN where they are registered
• Place of supply — the state the supply is considered to be made in
• For each line: description, HSN code, quantity, rate and amount
• The rate of tax applied to each line, and the tax amount shown separately
• The total, and the same total written in words
• Where applicable, the recipient's address for delivery if it differs from the billing address

Seller and buyer GSTIN

A GSTIN is fifteen characters. The first two digits are the state code, the next ten are the PAN of the business, the thirteenth is the entity number for that PAN, the fourteenth is a fixed blank character, and the fifteenth is a check digit. Because it embeds the state, a GSTIN is also what tells the two sides whether the sale crosses a state line.

Both parties' GSTINs have to match their registrations exactly. A transposed digit is not a formatting problem — it is a number that belongs to nobody, and it is the most common reason a buyer's tax claim runs into trouble.

Place of supply, and why it decides the tax

The place of supply is the state the sale is treated as happening in. When it matches the seller's state the tax is split into CGST and SGST; when it does not, the same total tax is charged as IGST instead. The rate is identical either way — only the split changes.

That is the whole mechanism. The example below is a sale from Gujarat to Maharashtra, so the tax appears as a single IGST figure. The guide linked at the foot of this page shows the same two lines billed within one state, where the same tax appears as two equal halves.

HSN codes

HSN is the code for the kind of goods, and it goes against each line. The number of digits required depends on the turnover of the business, which is a question for a CA — but the field itself is straightforward, and the same product should carry the same code every time you bill it.

Services use SAC codes instead, in the same field. An invoice for services with no codes at all is common for small businesses, and the table simply drops the column.

How the tax lines are shown

Tax is charged on each line, at the rate set on that line, and then shown separately in the totals. Where every line carries the same rate, a single tax row is enough. Where rates differ, the rates are broken out — each with its own taxable amount and its own tax — so the buyer can reconcile the invoice against their own records rate by rate.

The grand total is the sum of the taxable amounts plus the tax. Indian invoices then round that to the nearest rupee and print the difference as a round-off line, so the printed figures add up exactly.

What kind of document to raise

A tax invoice is raised on a taxable sale. A bill of supply is raised where no GST is charged on the sale. A credit note is raised when an invoice has to be reduced or reversed after the fact.

Which one applies to a given sale depends on the nature of the supply and on the registration of both parties. That is a question for a CA, and it is worth asking before the document is raised rather than after.

Common questions

What is the difference between an invoice and a tax invoice?

A tax invoice is an invoice on a taxable sale that carries the GST details — both GSTINs, the place of supply, and tax shown separately. An invoice that charges no GST is a different document.

Is a GSTIN compulsory on a GST invoice?

The seller's is, where the seller is registered. The buyer's is needed where the buyer is registered and needs to claim the tax — which is a question for a CA for your particular sale.

What is the difference between HSN and SAC?

HSN classifies goods and SAC classifies services. They occupy the same field on the invoice.

Can the tax be included in the rate instead of added?

Yes — a rate can be entered as tax-inclusive and the invoice will work the tax back out of it. The tax amount is still shown separately in the totals either way.