What a GST invoice must contain, under Rule 46

Rule 46 of the CGST Rules sets out every particular a tax invoice must carry. Here is the full list in plain English, the four fields people actually leave off, and what happens to your buyer's input tax credit when one is missing.

Updated 18 August 2026 · 7 min read

Rule 46 of the CGST Rules, 2017 lists the particulars a tax invoice must carry. It is a dull list, and that is exactly why invoices fail on it — the tax is usually right and a field is simply missing. An invoice short of a mandatory particular is not a valid tax invoice, and your buyer's input tax credit rests on it being one.

The full list

Every tax invoice must contain:

Name, address and GSTIN of the supplier.
A consecutive serial number, unique for the financial year, no longer than 16 characters, using only letters, digits, hyphen and slash.
Date of issue.
Name, address and GSTIN or UIN of the recipient, if they are registered.
Where the recipient is unregistered and the taxable value is ₹50,000 or more: their name and address, the address of delivery, and the State together with its code.
HSN code for goods, or SAC for services.
Description of the goods or services.
Quantity, with unit or Unique Quantity Code, for goods.
Total value of the supply.
Taxable value, after any discount or abatement.
Rate of tax — central, State, integrated, Union territory, and cess.
Amount of tax charged, broken out by each of those heads.
Place of supply along with the name of the State, for inter-state supplies.
Address of delivery, where it differs from the place of supply.
Whether tax is payable on a reverse charge basis.
Signature or digital signature of the supplier or their authorised representative.

The four that actually get left off

In practice the list above fails in a small number of predictable places.

1. Place of supply with the State name. Plenty of invoices carry a state code buried in the buyer's GSTIN and nothing else. On an inter-state supply the place of supply must appear as its own particular, with the State named. This is also the field that decides whether you charge IGST or CGST + SGST, so getting it wrong breaks two things at once — see the place of supply guide.

2. The reverse charge flag. A yes-or-no field that changes who owes the tax. Software often omits it entirely rather than printing "No", which leaves the position ambiguous on the face of the document.

3. The unregistered-recipient block above ₹50,000. Sellers treat B2C invoices as needing nothing about the buyer. Past ₹50,000 of taxable value that stops being true: name, address, delivery address, State and State code all become mandatory.

4. Signature or digital signature. Routinely dropped from system-generated PDFs. Rule 46 requires it, whether as a digital signature or the signature of an authorised person.

The serial number trips people up structurally rather than by omission. It must be unique across the financial year and at most 16 characters. Numbering schemes that concatenate branch, year and sequence overrun that limit and are rejected on upload — see RET191115.

How many HSN digits you need

Reporting a valid code at the wrong length is still a failure. The number of digits required scales with aggregate annual turnover, and the thresholds have been tightened by notification more than once — smaller businesses report fewer digits, larger ones must report more. Confirm the digit requirement for your current turnover band before you file, rather than assuming last year's setting still applies.

What a missing field actually costs

The immediate cost lands on your buyer. Input tax credit under Section 16 depends on holding a valid tax invoice, so a defective document puts their credit at risk — and they will notice at reconciliation, after they have paid you. For a marketplace or a larger buyer, that is the point at which payment stops.

For you, the correction is rarely a quiet edit. If the invoice has already been reported in GSTR-1, fixing it means a credit note or an amendment in a later return, not a re-issue under the same number.

Before you file

Both GSTINs present, 15 characters, correct structure.
Serial number unique for the year and 16 characters or fewer.
Place of supply present with the State named, on every inter-state supply.
Reverse charge stated explicitly, even when it is "No".
HSN or SAC present, at the digit length your turnover requires.
Tax heads consistent — CGST + SGST, or IGST, never a mix.
Taxable value × rate equals the tax shown, per line.
Signature or DSC present.

Most of these are mechanical, which means they are worth checking automatically rather than by eye. You can run a single invoice through the invoice checker, or a whole batch before filing with the bulk pre-filing check.

Not sure your invoice passes?

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This guide is general information about Indian GST law, not tax advice. Rates, caps and due dates change by CBIC notification — confirm the current position on cbic.gov.in or with your CA before you file.