The tax invoice is the document on which GST turns: it fixes the time of supply, it carries the tax, and it is the recipient's passport to credit. Section 31 sets when it must be issued, and the special documents that replace or supplement it.
Key points
- Under section 31(1) of the CGST Act, 2017 an invoice for goods must be issued before or at the time of removal for supply (or delivery, where there is no movement).
- An invoice for services must be issued within the prescribed period — generally thirty days of supply (Rule 47).
- A recipient paying reverse charge on supplies from an unregistered supplier must issue a self-invoice — from 01.11.2024 within thirty days of receipt (Rule 47A) — and a payment voucher on payment.
- E-invoicing on the Invoice Registration Portal applies to businesses with aggregate turnover above Rs. 5 crore in any year since 2017–18 (Rule 48(4)).
The provisions
31(1)–(2)When to issue the invoice
Statutory text
(1) A registered person supplying taxable goods shall, before or at the time of,-
(a) removal of goods for supply to the recipient, where the supply involves movement of goods; or
(b) delivery of goods or making available thereof to the recipient, in any other case, issue a tax invoice showing the description, quantity and value of goods, the tax charged thereon and such other particulars as may be prescribed:
Provided that the Government may, on the recommendations of the Council, by notification, specify the categories of goods or supplies in respect of which a tax invoice shall be issued, within such time and in such manner as may be prescribed.
(2) A registered person supplying taxable services shall, before or after the provision of service but within a prescribed period, issue a tax invoice, showing the description, value, tax charged thereon and such other particulars as may be prescribed:
1[Provided that the Government may, on the recommendations of the Council, by notification,-
(a) specify the categories of services or supplies in respect of which a tax invoice shall be issued, within such time and in such manner as may be prescribed;
(b) subject to the condition mentioned therein, specify the categories of services in respect of which-
(i) any other document issued in relation to the supply shall be deemed to be a tax invoice; or
(ii) tax invoice may not be issued.]
** Kindly also refer to Notification No. 66/2020 – CT dated 21st Sept., 2020.
1. Substituted for the proviso " Provided that the Government may, on the recommendations of the Council, by notification and subject to such conditions as may be mentioned therein, specify the categories of services in respect of which-
(a) any other document issued in relation to the supply shall be deemed to be a tax invoice; or
(b) tax invoice may not be issued."
by s. 123 of the Finance Act, 2020 (No. 12 of 2020) - Brought into force w.e.f. 01st January, 2021 vide Notification No. 92/2020-C.T. dated 22nd December, 2020.
31(3)Revised invoices, bills of supply, vouchers, self-invoices
Statutory text
(3) Notwithstanding anything contained in sub-sections (1) and (2)-
(a) a registered person may, within one month from the date of issuance of certificate of registration and in such manner as may be prescribed, issue a revised invoice against the invoice already issued during the period beginning with the effective date of registration till the date of issuance of certificate of registration to him;
(b) a registered person may not issue a tax invoice if the value of the goods or services or both supplied is less than two hundred rupees subject to such conditions and in such manner as may be prescribed;
(c) a registered person supplying exempted goods or services or both or paying tax under the provisions of section 10 shall issue, instead of a tax invoice, a bill of supply containing such particulars and in such manner as may be prescribed:
Provided that the registered person may not issue a bill of supply if the value of the goods or services or both supplied is less than two hundred rupees subject to such conditions and in such manner as may be prescribed;
(d) a registered person shall, on receipt of advance payment with respect to any supply of goods or services or both, issue a receipt voucher or any other document, containing such particulars as may be prescribed, evidencing receipt of such payment;
(e) where, on receipt of advance payment with respect to any supply of goods or services or both the registered person issues a receipt voucher, but subsequently no supply is made and no tax invoice is issued in pursuance thereof, the said registered person may issue to the person who had made the payment, a refund voucher against such payment;
(f) a registered person who is liable to pay tax under sub-section (3) or subsection (4) of section 9 shall 2[, within the period as may be prescribed,] issue an invoice in respect of goods or services or both received by him from the supplier who is not registered on the date of receipt of goods or services or both;
(g) a registered person who is liable to pay tax under sub-section (3) or subsection (4) of section 9 shall issue a payment voucher at the time of making payment to the supplier.
2[Explanation.––For the purposes of clause (f), the expression “supplier who is not registered” shall include the supplier who is registered solely for the purpose of deduction of tax under section 51.]
2. Inserted by section 122 of The Finance Act (No. 2) Act, 2024 No. 15 of 2024 dated 16.08.2024.
What it means
- (a) revised invoices for supplies made between the date of liability and the grant of registration, within one month of registration;
- (b) no invoice needed for supplies below Rs. 200 to unregistered persons, subject to conditions;
- (c) a bill of supply instead of a tax invoice for exempt supplies and by composition taxpayers;
- (d), (e) a receipt voucher on receiving an advance, and a refund voucher if no supply follows;
- (f) a self-invoice by a recipient paying reverse charge on supplies from an unregistered supplier — from 01.11.2024 "within the period as may be prescribed", which Rule 47A fixes at thirty days from receipt; the Explanation treats a supplier registered only for TDS as unregistered;
- (g) a payment voucher by a recipient paying reverse charge, at the time of payment.
31(4)–(7)Continuous supplies; ceased supplies; goods on approval
Statutory text
(4) In case of continuous supply of goods, where successive statements of accounts or successive payments are involved, the invoice shall be issued before or at the time each such statement is issued or, as the case may be, each such payment is received.
(5) Subject to the provisions of clause (d) of sub-section (3), in case of continuous supply of services,-
(a) where the due date of payment is ascertainable from the contract, the invoice shall be issued on or before the due date of payment;
(b) where the due date of payment is not ascertainable from the contract, the invoice shall be issued before or at the time when the supplier of service receives the payment;
(c) where the payment is linked to the completion of an event, the invoice shall be issued on or before the date of completion of that event.
(6) In a case where the supply of services ceases under a contract before the completion of the supply, the invoice shall be issued at the time when the supply ceases and such invoice shall be issued to the extent of the supply made before such cessation.
**(7) Notwithstanding anything contained in sub-section (1), where the goods being sent or taken on approval for sale or return are removed before the supply takes place, the invoice shall be issued before or at the time of supply or six months from the date of removal, whichever is earlier.
Explanation.-For the purposes of this section, the expression "tax invoice" shall include any revised invoice issued by the supplier in respect of a supply made earlier.
What it means
For a continuous supply of goods, an invoice accompanies each statement or payment. For continuous supply of services, the invoice is tied to the due date of payment, or to receipt of payment, or to the completion of the event the payment is linked to. Where a service ceases before completion, the invoice is issued when it ceases, for the part supplied. For goods sent on approval, sale or return, the invoice is due at the time of supply or six months from removal, whichever is earlier. Revised invoices count as tax invoices (Explanation).
Statutory text as published on the CBIC tax information portal, as on 03.10.2026; the numbered notes record each amendment. Official source
Common questions
- When must a GST invoice for services be issued?
- Within thirty days of supply under Rule 47 (forty-five days for banks and insurers), as prescribed under section 31(2) CGST.
- Who must generate e-invoices?
- Registered persons whose aggregate turnover exceeded Rs. 5 crore in any financial year from 2017–18 onwards, for B2B supplies and exports (Rule 48(4), from 01.08.2023).
- When must a self-invoice be issued for reverse charge purchases?
- From 01.11.2024, within thirty days of receiving the supply from an unregistered supplier (section 31(3)(f) and Rule 47A).
Commentary and case notes checked against the judgments and CBIC sources on 04.10.2026.
What it means
For goods: before or at the time of removal where the supply involves movement, otherwise at delivery or making available — showing description, quantity, value, tax and other prescribed particulars (Rule 46). For services: before or after provision but within the prescribed period — thirty days under Rule 47 (forty-five days for banks and insurers). The invoice date drives the time of supply under sections 12 and 13.
The provisos let the Government specify categories where invoices may be issued within a different time, or replaced by another document. E-invoicing under Rule 48(4) — reporting B2B invoices to the Invoice Registration Portal for an IRN — applies above an aggregate turnover of Rs. 5 crore from 01.08.2023 (Notification 10/2023-Central Tax); an invoice issued without an IRN where one is required is not a valid invoice.