Tax Invoice GST Rules explained: this guide covers what it means, who it applies to, the step-by-step process, documents required, fees, due dates and penalties in India — so you can stay compliant with confidence and avoid costly mistakes.
A tax invoice is the document that carries your GST liability and your customer's input tax credit. Get the contents or the timing wrong and you can lose credit for the buyer, pull your own liability into an earlier month, or end up with an invoice the law does not recognise. This article sets out the rules in section 31 and Rules 46 and 47 of the CGST Rules as a working checklist.
Under section 31, a supplier of goods issues the tax invoice before or at the time of removal of the goods (or at delivery, if nothing moves). A supplier of services issues it before or after the service, but within 30 days under Rule 47 (45 days for insurers, banks and financial institutions including NBFCs). The contents are fixed by Rule 46. GST law has no provision to revise an invoice just because it contains an error.
When the invoice must be issued
| Supply | Last time to issue | Source |
|---|---|---|
| Goods, with movement | Before or at the time of removal | Section 31(1)(a) |
| Goods, no movement | Before or at the time of delivery or making available | Section 31(1)(b) |
| Services | Before or after the service, within 30 days of the supply | Section 31(2), Rule 47 |
| Services by insurer, bank, financial institution, NBFC | Within 45 days | Proviso to Rule 47 |
| Continuous supply of services | By the due date of payment, at payment, or on completion of the event, as the contract provides | Section 31(5) |
| Services stopped midway | When the supply ceases, for the extent supplied | Section 31(6) |
| Goods sent on approval | Before or at supply, or six months from removal, whichever is earlier | Section 31(7) |
| Reverse-charge self-invoice from an unregistered supplier | Within 30 days of receipt of the supply | Section 31(3)(f), Rule 47A |
The deadline is not only a compliance point. For services, an invoice inside the window lets the time of supply follow the invoice date. A late invoice moves it back to the date the service was provided, as explained in time of supply of services. For a separate walk-through of each document's timeline, see Rule 47 and 47A.
Illustration: a consultant completes an assignment on 10 October 2026 and raises the invoice on 20 November 2026. That is 41 days later, outside the 30-day window, so GST is due from the earlier of the completion date and the date payment is received.
If invoices are going out late across your billing cycle, a GST health check will show which months are affected.
What Rule 46 requires on every tax invoice
A tax invoice must carry:
- name, address and GSTIN of the supplier;
- a consecutive serial number of up to 16 characters, unique for the financial year, using letters, numerals, hyphen and slash (more than one series is allowed);
- the date of issue;
- name, address and GSTIN or UIN of a registered recipient;
- HSN code, description, quantity and unit (for goods), total value and taxable value after discount or abatement;
- rate and amount of tax (central, State, integrated, UT tax, cess);
- place of supply with State name for inter-State supplies, and delivery address if different;
- whether tax is payable on reverse charge;
- signature or digital signature of the supplier or authorised representative.
The signature is not required on an electronic invoice issued under the Information Technology Act, 2000. For e-invoices the QR code with the IRN is also required. A taxpayer above the e-invoice turnover limit who issues a normal invoice must carry the declaration in clause (s). See the e-invoicing article for the IRN rules.
Recipient details: registered and unregistered buyers
For an unregistered buyer, the recipient's name, address, delivery address and State with code are needed where the taxable value is Rs. 50,000 or more. Below Rs. 50,000 they are needed only if the buyer asks. The exceptions are supplies of online money gaming and taxable services supplied by or through an e-commerce operator or by an OIDAR supplier to an unregistered recipient: name, address, PIN code and State are required whatever the value.
Exports need an endorsement that the supply is meant for export (or to an SEZ unit or developer) on payment of IGST, or under bond or letter of undertaking without payment of IGST, plus the country of destination instead of the State.
HSN digits, copies and small invoices
The Background Material records the HSN rule in force from 1 April 2021: up to 4 digits where the previous year's aggregate turnover was up to Rs. 5 crore, and 6 digits above that. A taxpayer up to Rs. 5 crore need not show the digits on invoices to unregistered buyers.
Copies: an invoice for goods is prepared in triplicate (original for recipient, duplicate for transporter, triplicate for supplier) and for services in duplicate. This does not apply to an e-invoice.
Section 31(3)(b) lets a registered person skip the invoice where the value is under Rs. 200, provided the recipient is unregistered and does not want one, and a consolidated invoice is issued at the close of each day. Multiplex operators are excluded and must issue an electronic ticket.
Special documents exist for insurers and banks (a consolidated monthly invoice under Rule 54(2)), goods transport agencies, passenger transport and cinema tickets. Discount is reduced from taxable value only if it is shown on the face of the invoice.
Mistakes: no revised invoice
The Background Material is explicit that there is no provision to revise an invoice because of an error. A revised invoice exists only for supplies made between the effective date of registration and the date of the registration certificate, and it must be issued within one month of the certificate. Wrong value or tax after supply is handled through a credit note or debit note under section 34, covered in the credit note article. For the pre-registration case, see revised invoices after registration.
Need help with invoicing rules?
If your invoices are missing fields, carrying duplicate numbers or going out after the 30-day window, the problem usually shows up later as buyers' credit queries or return mismatches. Our team can review a sample of your invoices against Rule 46 and Rule 47 and tell you what to correct, through a GST health check. Once the template is right, GSTR-1 filing becomes a straightforward report of what you issued.
Key takeaways
- Goods: invoice at or before removal or delivery. Services: within 30 days (45 for insurers, banks, NBFCs).
- Rule 46 fixes the contents, including a 16-character unique serial number.
- Unregistered buyers: full details from Rs. 50,000, otherwise on request.
- Invoices under Rs. 200 to unregistered buyers can be covered by a daily consolidated invoice.
- There is no revision of an invoice for errors. Use a credit or debit note.
Read next
- E-invoicing under GST: applicability and IRN rules
- Bill of supply, receipt voucher and refund voucher
- Rule 46: every particular a tax invoice must carry
- Invoice numbering: sixteen characters and two symbols
Disclaimer: Positions stated as on 30 September 2026, based on the CGST and IGST Acts and Rules as amended, the Finance Act 2026, and the ICAI Background Material on GST (14th Edition, July 2026). Verify current notifications before acting.