GST invoice format in India: the fields that actually matter

An invoice that is missing the right details is not just an administrative problem. It can delay your payment, because a finance team that cannot reconcile an invoice will simply put it back in the queue. GST made this stricter: a tax invoice has to carry certain information to be valid.

What a tax invoice is for

Under GST, a registered business issues a tax invoice when it makes a taxable supply of goods or services. The invoice tells the buyer what they bought, how much GST applies, and how the tax splits between central and state governments. For the buyer, it is the document that supports claiming input tax credit.

The fields a GST invoice should carry

• A unique invoice number, issued in a consecutive series, kept within the allowed length.
• The date the invoice was issued.
• Your legal name, address and GSTIN.
• The recipient's name, address and GSTIN where they are registered.
• The place of supply, which determines whether you charge CGST and SGST or IGST.
• A description of the goods or services supplied.
• HSN codes for goods or SAC codes for services, where applicable.
• Quantity and unit, for goods.
• Taxable value — the amount before tax.
• The GST rate applied and the tax amount, shown separately as CGST and SGST or as IGST.
• Any discount or other adjustment, shown clearly.
• The total invoice value, ideally in words as well as figures.
• Your signature or digital signature.

If you are supplying to a customer in another state, the tax splits as IGST. For a supply within your own state, it splits into CGST plus SGST. Getting this wrong is one of the most common reasons an invoice gets rejected by a client's accounts team.

Tax invoice, bill of supply, or e-invoice?

Tax invoice

Used for taxable supplies. It shows the tax rate and the GST charged, and it is what your customer needs in order to claim input tax credit.

Bill of supply

Used when no GST is chargeable — for example by a composition-scheme dealer, or for exempt and nil-rated supplies. It looks similar to an invoice but must not show a tax amount, and it cannot be used to claim input tax credit.

E-invoice

E-invoicing is the electronic reporting of business-to-business invoices to the GST system, which returns an Invoice Reference Number. It applies to businesses above a turnover threshold notified by the GST Council — five crore rupees and above at the time of writing. That threshold has been lowered several times, so verify the current limit on the GST portal before assuming e-invoicing does not apply to you.

A practical invoice checklist

1. Is the invoice number unique and part of a consecutive series?
2. Is the invoice date correct and after the supply was made?
3. Are your GSTIN and legal name exactly as registered?
4. Have you captured the client's GSTIN if they are registered?
5. Is the place of supply right, and does the tax split match it?
6. Are HSN or SAC codes present where they are required?
7. Does the arithmetic add up, including any discount?
8. Is the payment due date stated clearly?

Mistakes that slow payment down

• Wrong place of supply, so the CGST/SGST and IGST split is wrong.
• A missing or incorrect client GSTIN, which blocks their input tax credit claim.
• No purchase order reference, so the client cannot match the invoice to what they ordered.
• Vague line items such as "consulting services" with no period or description.
• No due date, leaving the client to guess when payment is expected.

Most of these are avoidable with a template that pre-fills the parts that never change and prompts for the parts that do. That is one of the things we are building into Fintog, so that a compliant invoice is also a fast one to raise.

Updated 24 October 2026. This article is general guidance from the team building Fintog, not tax, legal or accounting advice.