GST Invoice Format: Every Mandatory Field Under Rule 46

The sixteen particulars Rule 46 requires

Rule 46 is specific. A tax invoice issued by a registered person must contain:

Nothing in that list dictates a layout. You can present these in any visual arrangement your accounting system produces, which is why two compliant invoices can look entirely different.

• Name, address and GSTIN of the supplier.
• A consecutive serial number, unique within a financial year, not exceeding sixteen characters, using only letters, numerals, hyphens and slashes.
• Date of issue.
• Name, address and GSTIN or UIN of the recipient, where the recipient is registered.
• Name and address of the recipient and the delivery address, with the State and its code, where the recipient is unregistered and the value exceeds fifty thousand rupees.
• HSN code for goods or SAC for services.
• Description of the goods or services.
• Quantity, with unit of measure, for goods.
• Total value of the supply.
• Taxable value, after any discount or abatement.
• Rate of tax, split between central tax, State tax, integrated tax, Union territory tax and cess.
• Amount of tax charged, split the same way.
• Place of supply, with the State name, for inter-State supplies.
• Address of delivery where it differs from the place of supply.
• Whether tax is payable on reverse charge.
• Signature or digital signature of the supplier or an authorised representative.

How many HSN digits you must show

The digit requirement is tied to aggregate annual turnover in the preceding financial year, not to the value of the individual invoice. Businesses up to five crore rupees must show four digits on B2B supplies and may omit HSN on B2C. Above five crore, six digits are required on every tax invoice.

Getting this wrong is one of the commonest reasons an invoice is challenged, and it is entirely mechanical — the HSN for what you sell does not change from month to month, so it belongs in your item master rather than being typed each time.

The invoice number rules people break most often

The serial number must be consecutive, unique within the financial year, and no longer than sixteen characters. Three mistakes recur:

1. Restarting mid-year: the series runs for the financial year, so restarting at 001 in October creates duplicates.

2. Gaps in the series: a cancelled invoice number must still be accounted for, not skipped silently.

3. Unsupported characters: only alphabets, numerals, hyphen and slash are permitted. Hash symbols, spaces and underscores are not.

If you run multiple series — one per branch or per business vertical — each must be internally consecutive and separately identifiable. The law permits multiple series; it does not permit an unexplained jump inside one.

CGST and SGST, or IGST: the place of supply decides

The split is not a choice. If the place of supply is in the same State as the supplier, the transaction attracts central tax and State tax in equal halves. If it falls in a different State, or the supply is an export or to an SEZ, integrated tax applies at the full rate.

For goods, the place of supply is generally where movement terminates for delivery. For services the default is the location of the registered recipient, with a long list of exceptions — immovable property, events, transport, telecom and others — each with its own rule. Charging CGST and SGST where IGST was due means your customer cannot offset the credit in their State, and the correction requires a credit note and a fresh invoice.

When a bill of supply replaces a tax invoice

Not every document is a tax invoice. A registered person supplying exempted goods or services, or paying tax under the composition scheme, issues a bill of supply instead. It carries no tax amount, and the composition dealer must state on it that they are not eligible to collect tax.

Mixing these up has consequences in both directions: charging GST on a bill of supply is a collection without authority, and issuing a bill of supply for a taxable sale understates your liability.

Time limits for issuing the invoice

For goods involving movement, the invoice must be issued before or at the time of removal. Where no movement is involved, it is issued on delivery or when the goods are made available. For services the limit is thirty days from the date the service is supplied, extended to forty-five days for insurers, banks and financial institutions.

A continuous supply of services is invoiced by the due date stated in the contract, or on receipt of payment where no date is fixed, or on completion of the event where payment is linked to one.

Frequently asked questions

### Is there an official GST invoice format to download?

No. The government prescribes particulars, not a layout. Rule 46 of the CGST Rules lists the fields a tax invoice must carry; how you arrange them on the page is yours to decide. Any template you download is somebody's interpretation of Rule 46, which is why they all look different while being equally valid.

### How many copies of a tax invoice must I make?

For a supply of goods, three: the original marked for the recipient, the duplicate for the transporter, and the triplicate for the supplier. For services, two: the original for the recipient and the duplicate for the supplier. With electronic invoicing the practical relevance has faded, but the rule remains in Rule 48.

### Can I issue a GST invoice without a GSTIN?

Not a tax invoice. Only a registered person can issue one and collect GST. An unregistered supplier may raise an ordinary bill or cash memo but cannot charge GST on it, and the recipient cannot claim input credit against it. Collecting tax without registration is an offence under Section 122.

### What happens if an invoice is missing a mandatory field?

It stops being a valid tax invoice under Rule 46, which puts your customer's input tax credit at risk, since Section 16(2)(a) requires possession of a valid invoice. In practice the issue surfaces during a departmental audit of the recipient, who then pushes the problem back to you along with the interest they have been charged.

### Does the invoice have to be signed?

Yes — by the supplier or an authorised representative, physically or digitally. The one exception is an invoice issued electronically in accordance with the Information Technology Act 2000 requirements, where a digital signature is not separately required because the issuing mechanism already authenticates it.