GST Invoice Mandatory Fields: Rule 46 Checklist for India

The direct answer: Rule 46 of the CGST Rules, 2017

The rule that governs the content of a tax invoice is Rule 46 of the Central Goods and Services Tax Rules, 2017. It is made under Section 31 of the Central Goods and Services Tax Act, 2017 and opens by saying that a registered person must issue a tax invoice containing the listed particulars, subject to Rule 54. The text is published by the Central Board of Indirect Taxes and Customs (CBIC) on its tax repository, and that official text is the one to rely on.

Many blogs say a GST invoice has 16 mandatory fields. The official clauses run from (a) to (q), with a proviso for exports and supplies to SEZ units. The gap comes from how each writer groups the items, not from a different law. When you check a draft, go by the clause letters in the CBIC text rather than by a headline count.

The clauses that apply to almost every invoice are the supplier's name, address and GSTIN (clause a), the serial number (clause b), the date of issue (clause c), the HSN or SAC code (clause g), the description (clause h), the quantity and unit for goods (clause i), the total value (clause j), the taxable value after any discount or abatement (clause k), the tax rate and tax amount (clauses l and m), and the signature or digital signature of the supplier or its authorised representative (clause q).

How to work out the field list, step by step

Start with the buyer, because the buyer decides which of the buyer fields apply. Then work through the invoice from top to bottom. The order below follows the clause letters so you can tick each one against the CBIC text.

1. Check the heading and supplier block. The invoice must identify the supplier by name, address and GSTIN under clause (a). The serial number under clause (b) must be no more than 16 characters, may use letters, numbers, hyphens and slashes, and must be unique for the financial year.
2. Add the date of issue under clause (c). Record the same date the invoice is actually issued, because the time limits for issuing an invoice run from that point.
3. Identify the buyer under clause (d). If the buyer is registered, record the buyer's name, address and GSTIN or Unique Identity Number. If the buyer is not registered, go to the next step.
4. For an unregistered buyer, look at the taxable value of the supply. Clause (e) requires the name and address of the recipient, the address of delivery, the name of the State and its code where the taxable value is Rs 50,000 or more. Clause (f) covers invoices below Rs 50,000, where the same details are needed only if the buyer asks for them.
5. Describe what was sold. Record the HSN code for goods or the accounting (SAC) code for services under clause (g), the description under clause (h), and the quantity and unit under clause (i). Clause (i) refers to the unit of measure, using the Unique Quantity Code for goods.
6. Record the values. Show the total value under clause (j) and the taxable value after discount under clause (k). Discounts that reduce the taxable value must be reflected here, not hidden in the total.
7. Show the tax. Show the rate under clause (l) and the amount under clause (m), split into central, State, integrated, Union territory tax or cess as applicable.
8. Add the place of supply under clause (n) for interstate supplies, with the State name and its code. Add the delivery address under clause (o) where it differs from the place of supply. Add the reverse-charge statement under clause (p) where it applies.
9. Sign it. Add the signature or digital signature of the supplier or its authorised representative under clause (q).

Side by side: B2B, larger B2C, smaller B2C and interstate invoices

The same invoice can need different buyer fields depending on who receives it and where the goods or services go. The table below shows what changes. Everything not shown in the table, such as the supplier block, serial number, date, HSN, description, values and tax, applies to every invoice.

The table shows a pattern worth remembering. The threshold of Rs 50,000 changes the buyer details, not the tax arithmetic. An interstate sale to a registered buyer needs the buyer's GSTIN and a place of supply. An interstate sale to an unregistered buyer below Rs 50,000 needs a place of supply, while the buyer's details are added only on request.

Worked example: an interstate sale to a registered buyer

Suppose a computer supplier in Pune, Maharashtra (State code 27) sells five laptops to a company in Bengaluru, Karnataka (State code 29). The company is registered, so it has a GSTIN. The laptops are classed under HSN 8471 and the unit of measure is numbers. The list price is Rs 20,000 per unit, so the total value is Rs 1,00,000. A trade discount of Rs 5,000 is given on the invoice. The rate used here is 18 per cent, for illustration only.

• Taxable value after discount: Rs 1,00,000 less Rs 5,000, giving Rs 95,000 (clause k).
• Integrated tax at 18 per cent: Rs 17,100 (clauses l and m). Because the sale crosses a State boundary, the tax is shown as IGST, not CGST and SGST.
• Invoice total: Rs 1,12,100 (clause j shows the total value of the supply).

The invoice must also show the supplier's name, address and GSTIN, a serial number such as a financial-year series, the date, the buyer's name, address and GSTIN, the HSN code, the description, the quantity of five numbers, the place of supply as Karnataka with its code 29, and the signature. Leaving out the place of supply on this invoice is one of the most common errors, and it is the one that is easiest to spot in a review.

Cases that change the answer

Several situations add or remove items from the basic list. None of them removes the core fields.

Exports and supplies to SEZ units. The proviso to Rule 46 requires a specific endorsement on the invoice for exports of goods or services and for supplies to a Special Economic Zone unit or developer. The wording is set out in the rule and should be copied exactly from the CBIC text, not from a template you have not checked.

Reverse charge. Clause (p) requires the invoice to say whether tax is payable on a reverse-charge basis. Many invoices have no reverse-charge supply, but the statement should still be checked on every invoice.

Bill-to and ship-to. When goods go to a different address from the buyer's billing address, clause (o) adds the delivery address. This matters most for distributors and contractors who invoice head offices but ship to project sites.

Special cases under Rule 54. The opening words of Rule 46 say it applies subject to Rule 54. Rule 54 deals with tax invoices in special cases, so a supplier in those categories should confirm which format applies to them.

Electronic invoicing. Businesses above the turnover limit notified under the e-invoicing rules must also carry an Invoice Reference Number and a signed QR code, which are generated through the Invoice Registration Portal. The turnover limit has been changed by notification in the past, so the current figure and the rule number should be confirmed with your accountant before you rely on it.

Common mistakes

• Writing cash customer or no name on an unregistered sale of Rs 50,000 or more. Clause (e) asks for the buyer's name, address and delivery details in that case.
• Reusing a serial number from an earlier financial year. Clause (b) requires uniqueness within the financial year, and a series that restarts must be unique for that year.
• Leaving out the place of supply on interstate invoices, or writing the State name without its code.
• Showing a total that does not match the taxable value and tax lines, or failing to show the discount in the taxable value.
• Using a generic description such as items or services. The description must identify what was actually supplied.
• Copying an invoice template that was built for a different case, such as a B2B template used for a small cash sale.

Check a draft before you send it

Use the free calculator on this page to check a draft invoice before it leaves your office. Work through the following steps in order.

1. Identify the buyer type first: registered, unregistered with value of Rs 50,000 or more, or unregistered below Rs 50,000.
2. Confirm whether the supply crosses a State boundary, and if so, add the place of supply with the State name and code.
3. Tick each clause letter from (a) to (q) against the draft, and mark the ones that do not apply to this invoice, such as the export endorsement.
4. Check the taxable value, tax lines and total against each other, using the discount figure you actually gave.
5. Compare the final layout with the CBIC text once a year, because the rules and the turnover thresholds are changed by notification.

What to check with your accountant or a lawyer

Some questions need a person who knows your business. Ask your accountant whether your turnover puts you under the e-invoicing requirement, which HSN digit count applies to your products, and whether any special-case rule covers your activity. Ask whether your billing software produces the fields in the right layout, and whether your records can show the buyer's details when a return is checked. If you are unsure how the rule applies to a particular transaction, a tax lawyer or chartered accountant should decide it, not a template.

How employers take routine invoicing and payroll paperwork off staff

Many employers spend a large part of each month on routine paperwork: raising invoices, chasing buyer details, matching payments, preparing payroll inputs and filing records. AiStaffo builds AI workers that take over this kind of routine business work, including data entry, follow-ups, reconciliations, billing and documents. In practice, the worker reads the source records, fills the standard fields, flags anything missing, and passes the draft to a person. The person still approves, signs and sends the document, and the company still owns the decision on any tax treatment. The tool links the invoice to the company's own figures, which the free audit measures.

This explains the rule in general terms; it is not legal or tax advice for your case.