Section 13 — Time of Supply of Services | GST Act

1. What Section 13 does

Section 13 determines the time of supply of services. In practical terms, it answers the question: “In which tax period does the GST liability on this service arise?”

This is different from asking whether a service is taxable, what rate applies, where the service is supplied, or what its value is. Those are separate legal questions. Section 13 focuses on the timing of the tax liability.

Core principle: The date on which a customer actually pays is not automatically the date on which GST becomes payable. Under the normal rule, invoice timing, the legally prescribed invoice deadline, payment and the actual provision of service have to be tested in the sequence laid down by Section 13.

This distinction is particularly important for construction contracts, professional retainers, annual maintenance contracts, government works, consulting assignments, software services, subscriptions, recurring services and supplies where invoices are raised after certification or milestone completion.

CBIC's sectoral FAQs specifically explain that terms of payment do not by themselves determine GST liability. For example, in construction work, delay by the client's engineer in verifying an invoice does not automatically postpone the time of supply where the statutory invoice trigger has already arisen. citeturn0search0

2. Complete statutory structure of Section 13

Provision	Subject	What the provision does
13(1)	Basic liability	Tax liability on services arises at the time of supply determined under Section 13.
13(2)	Normal forward-charge service	Uses invoice/payment/provision-of-service/recipient-book triggers in a prescribed sequence.
13(3)	Reverse charge	Provides a separate timing mechanism where the recipient is liable to pay tax.
13(4)	Vouchers — historical provision	Former voucher-specific rule; this sub-section was omitted with effect from 1 October 2025.
13(5)	Residual cases	Fallback rule where time of supply cannot be determined under the preceding applicable provisions.
13(6)	Interest / late fee / penalty	Time of supply for additional value arising from delayed payment is linked to receipt of that addition.

Current-law point: The most important recent structural development is the Finance Act 2025 omission of Section 13(4). The current law should therefore not present the former voucher rule as an operative 2026 rule.

The April 2026 bare-law text records the 2018 amendment to Section 13(2)(a), the 2024 amendments to Section 13(3), and the omission of Section 13(4). The 2024 changes became effective from 1 November 2024 through Notification No. 17/2024-Central Tax. citeturn2search29turn2search9

3. Normal supply of services — Section 13(2)

For a normal forward-charge service, Section 13(2) uses an earliest-date framework. The exact test depends first on whether the supplier has issued the invoice within the period prescribed under Section 31.

Case A — invoice issued within the prescribed period

Time of supply = earlier of:

date of issue of invoice; or
date of receipt of payment.

Case B — invoice not issued within the prescribed period

Time of supply = earlier of:

date of provision of service; or
date of receipt of payment.

Case C — neither of the above determines the time

The time of supply becomes the date on which the recipient records the receipt of the service in its books of account, where the statutory conditions for this residual clause are satisfied.

The current statutory text also retains the ₹1,000 excess-payment proviso: where the supplier receives an amount up to ₹1,000 in excess of the amount shown in the tax invoice, the supplier may, for that excess, opt to treat the invoice date as the time of supply. citeturn2search24

Why the sequence matters

Suppose a contractor completes work on 20 June, is required to invoice within the statutory period, actually issues the invoice on 25 June and receives payment on 15 August. The payment date does not automatically shift the GST liability to August. If the invoice was issued within the prescribed period, Section 13(2)(a) requires the invoice date and payment date to be compared, and the earlier date controls.

Conversely, if the supplier fails to issue the invoice within the prescribed statutory period, Section 13(2)(b) becomes relevant. The analysis then shifts from invoice date to the date of provision of service and receipt of payment.

4. Invoice timing cannot be separated from Section 31

Section 13 deliberately refers to the period prescribed under Section 31. Therefore, a proper time-of-supply working should never consider Section 13 in isolation.

Question	Why it matters
When was the service supplied?	Establishes the underlying service event.
What type of service?	May affect the invoice rule and continuous-supply treatment.
When was the invoice legally required?	Determines whether Section 13(2)(a) or 13(2)(b) applies.
When was the invoice actually issued?	Relevant for the earliest-date test.
When was payment received?	Relevant to the payment trigger.
Was there continuous supply?	Section 31(5) can determine the invoice point by contractually specified events or payment dates.

For ordinary taxable services, Rule 47 generally provides a 30-day invoice period, while specified suppliers such as insurers and banking companies/financial institutions have special periods. The invoice rule must be read with the applicable statutory and rule provisions for the period under review. citeturn0search39

Professional conclusion: “Invoice issued within 30 days” is only a shortcut for common cases. The actual legal test is whether the invoice was issued within the period prescribed under Section 31 and applicable rules for that particular supply.

5. What exactly is “date of receipt of payment”?

Section 13 contains an explanation for the payment trigger. The date of receipt of payment is the earlier of:

Books of account
The date on which the payment is entered in the supplier's books of account.

Bank account
The date on which the payment is credited to the supplier's bank account.

This prevents a supplier from postponing the time-of-supply analysis merely by choosing a later accounting date when the amount has already been credited to the bank, or vice versa.

Practical control

For material services, retain a payment trail showing:

customer payment reference;
bank credit date;
date posted in the books;
invoice number;
contract / work order reference;
GST period in which the liability was reported.

Advance payments: Unlike the special operational relief historically granted for advances relating to goods, services have generally remained subject to the payment trigger in Section 13. The GST Council's 25th-meeting material expressly records the policy decision that GST should continue to be levied on receipt of advances in the case of services. citeturn1search3

6. Continuous supply of services — why Section 31(5) matters

Construction, operation and maintenance contracts, annual maintenance arrangements, long-term consultancy, facility management and similar arrangements can involve services supplied continuously over a period rather than one isolated event.

For these arrangements, the time-of-supply analysis under Section 13 must be read together with the invoice provisions applicable to continuous supply of services.

Contract arrangement	Invoice/event consideration	Section 13 consequence
Payment due on a specified date	Invoice is linked to the specified payment date.	Section 13(2) tests the invoice/payment timing.
Payment linked to completion of an event	Invoice is linked to completion of that event.	The contractual milestone becomes important evidence of the statutory invoice point.
Periodic service without a single completion event	Periodic invoice arrangement is examined.	Time of supply follows the Section 13 framework with the applicable Section 31 invoice requirement.

CBIC guidance on construction services explains that the terms of the contract and statutory invoice rules determine the GST timing; delayed payment by the customer does not by itself postpone the time of supply. citeturn0search0

Important for construction businesses: RA bills, milestone certificates, measurement books, engineer certification and payment schedules should be mapped to the contractual event that triggers invoicing. Do not treat the date of cash collection as the only tax-date evidence.

7. Advances for services — detailed treatment

For services, receipt of an advance can be relevant to the time-of-supply determination under Section 13(2). This is a major distinction from the practical relief granted for advances received for goods.

Example

A consultant receives ₹10 lakh advance on 10 April. The service is performed in June and the invoice is issued in July. If the payment trigger under Section 13(2) applies earlier than the other statutory triggers, the advance can create GST liability in April.

Control point: The finance team should not assume that “no invoice = no GST” for a service advance. Section 13 expressly includes receipt of payment in the normal time-of-supply test.

What to document

advance receipt date;
customer and contract reference;
nature of service for which advance was received;
taxable value and GST calculation;
later adjustment against invoice;
GSTR-1/GSTR-3B reporting trail;
credit/debit adjustments, if any.

8. Reverse charge — Section 13(3)

Reverse charge changes the identity of the person responsible for paying GST. Consequently, Section 13(3) uses a separate time-of-supply mechanism for services on which tax is paid or is liable to be paid under reverse charge.

Under the current framework, the basic test is the earliest of the applicable payment and invoice-related triggers. The 2024 amendment added an important third situation where the recipient itself is required to issue the invoice.

Trigger A
Date of payment as entered in the recipient's books, or date the recipient's bank account is debited, whichever is earlier.

Trigger B
Date immediately following 60 days from the supplier's invoice/document, where the supplier is required to issue the invoice.

Trigger C — from 1 Nov 2024
Date of issue of invoice by the recipient, where the recipient is required to issue the invoice.

Fallback
If the time cannot be determined under the applicable triggers, the statutory fallback is the date of entry in the recipient's books of account.

The 53rd GST Council meeting specifically identified the ambiguity created where Section 13(3)(b) referred to an invoice issued by the supplier even though Section 31(3)(f) could require the recipient to issue the invoice. The Council recommended a separate clause for the recipient-issued invoice scenario. citeturn1search0

9. RCM where the supplier issues the invoice

Where the supplier is responsible for issuing the invoice, Section 13(3)(b) uses the date immediately following 60 days from the supplier's invoice or equivalent document as one of the possible triggers.

This does not mean that 60 days automatically becomes the time of supply in every RCM service. The rule says the time of supply is the earliest applicable date after comparing it with the payment trigger.

Event	Date	Result
Payment entered in books	10 May	Potential trigger
Bank account debited	12 May	Compare with books; earlier payment date governs
Supplier invoice	1 April	61st-day trigger arises later
Section 13(3) conclusion	—	Earliest applicable statutory trigger determines time of supply

Practical control: Maintain an RCM ageing report showing supplier invoice date, 60-day date, payment date, self-invoice date where applicable, accounting date and GST payment month.

10. RCM where the recipient issues the invoice — major 2024 change

This is one of the most important recent amendments to Section 13.

Finance (No. 2) Act, 2024 amended Section 13(3) so that where an invoice is required to be issued by the recipient, the time of supply includes the date of issue of the invoice by the recipient. The amendment was brought into force from 1 November 2024 by Notification No. 17/2024-Central Tax dated 27 September 2024. citeturn2search9

Why the amendment was needed

The GST Council's 53rd-meeting agenda explained the problem clearly: Section 13(3)(b) referred to an invoice issued by the supplier, while Section 31(3)(f) required the recipient to issue an invoice in specified RCM cases involving an unregistered supplier. This created an obvious mismatch in the statutory timing mechanism. citeturn1search0

Current three-way RCM test

Situation	Relevant Section 13(3) trigger
Payment by recipient	Earlier of book-entry payment or bank debit.
Supplier is required to issue invoice	Date immediately following 60 days from supplier's invoice/document.
Recipient is required to issue invoice	Date of issue of recipient's invoice.

Implementation date: The recipient-invoice clause is applicable from 1 November 2024. Historical RCM transactions before that date must be analysed under the law applicable at that time rather than retrofitting the 2024 clause.

11. Associated enterprises — special cross-border timing

Section 13 contains a special rule for supplies by an associated enterprise where the supplier of service is located outside India.

In that situation, the time of supply is the date of entry in the books of account of the recipient or the date of payment, whichever is earlier.

Important: Actual cash remittance is not the only event to monitor. The recipient's accounting entry itself can trigger the time-of-supply analysis.

Example

An Indian company receives management support from its overseas associated enterprise. The Indian entity records the service cost in its books on 31 March, while payment is made on 30 June. Where the statutory associated-enterprise rule applies, 31 March can be the earlier trigger.

GST Council explanatory material has specifically highlighted this special rule for associated enterprises and explained that the liability can arise even where no actual payment has yet taken place. citeturn1search15

12. Voucher provision — historical Section 13(4)

Historically, Section 13(4) contained a specific rule for vouchers: the time of supply was the date of issue where the supply was identifiable at that point, or the date of redemption in other cases.

Current law: Section 13(4) was omitted with effect from 1 October 2025. It should therefore be treated as historical law when reviewing older transactions, not as an operative 2026 rule. citeturn2search29

This distinction is particularly important in audits involving gift cards, prepaid instruments, customer incentives and promotional vouchers spanning multiple financial years.

13. Residual rule — Section 13(5)

If the time of supply cannot be determined under the applicable preceding provisions, Section 13(5) provides a fallback framework.

Situation	Fallback
Normal case where the preceding tests cannot determine the time	Date on which the recipient shows the receipt of service in its books, where applicable under Section 13(2), or the statutory residual mechanism under Section 13(5).
RCM case where Section 13(3) triggers cannot determine the time	Date of entry in the books of account of the recipient under the proviso to Section 13(3).

The important professional principle is that a residual rule should be used only after documenting why the ordinary statutory triggers did not determine the time of supply.

14. Interest, late fee and penalty for delayed payment

Section 13(6) deals with an addition in the value of supply by way of interest, late fee or penalty for delayed payment of consideration.

Rule: To the extent the time of supply relates to such an addition, it is the date on which the supplier receives that additional amount.

This creates a separate timing event from the original service supply.

Example

A contractor's service invoice is taxable in April. The customer delays payment and pays contractual interest in August. The GST treatment of the interest addition has its own Section 13(6) time-of-supply trigger when the supplier receives that additional amount.

This should be separately mapped in the accounts and GST working rather than automatically merging the interest amount into the original invoice period.

15. Amendment & development timeline — Section 13 from 2017 to 2026

1 July 2017 — GST commencement: Section 13 became operative as the statutory framework for determining time of supply of services.

2017 — original structure: The original framework contained normal forward-charge rules, reverse-charge rules, vouchers, residual provisions and interest/late-fee/penalty treatment. The original GST Council draft itself shows the architecture. citeturn0search3

1 February 2019 — Section 13(2)(a) drafting correction: The CGST (Amendment) Act, 2018 removed the words “sub-section (2) of” from the Section 31 reference, leaving the broader reference to the prescribed Section 31 invoice period. The change was brought into force from 1 February 2019. citeturn2search29

2019 — simplification discussions: GST Council discussions considered amendments to the time-of-supply provisions, including removing certain payment-related provisions for goods and simplifying the framework. The 25th Council agenda records the policy distinction that advances should continue to be taxed for services. citeturn1search3

16 August 2024 — Finance (No. 2) Act, 2024: Section 117 amended Section 13(3) to specifically address recipient-issued invoices in RCM cases. citeturn2search9

1 November 2024 — RCM amendment effective: Notification 17/2024-Central Tax brought the Section 13(3) amendments into force. The recipient-issued invoice became an express time-of-supply trigger. citeturn2search9

2024 — GST Council clarification of the legislative issue: The 53rd and 54th Council materials record the ambiguity in the earlier law and the Law Committee's recommendation for the recipient-invoice solution. citeturn1search0turn1search1

1 October 2025 — voucher rule omitted: Section 13(4) was omitted, removing the former voucher-specific time-of-supply rule from the current statute. citeturn2search29

2026 current position: Section 13 operates through normal service timing, RCM timing including the recipient-invoice trigger, associated-enterprise treatment, residual rules and delayed-payment additions, while the former voucher sub-section is no longer operative.

16. GST Council and legislative development

Section 13 is a useful example of why professional GST research should distinguish between the original statutory design, GST Council recommendations, enacted amendments and effective dates.

Development	Why it matters
Original GST Council drafting	Shows the initial policy architecture of time of supply.
2018 amendment	Corrected the Section 31 reference in Section 13(2)(a).
2024 Law Committee / Council recommendation	Identified the mismatch between supplier-issued and recipient-issued RCM invoices.
Finance (No. 2) Act 2024	Converted the 2024 recommendation into an enacted amendment.
Notification 17/2024-CT	Specified 1 November 2024 as the effective date.
Finance Act 2025	Omitted the voucher-specific Section 13(4).

Professional research rule: A Council agenda can explain why a change was proposed, but the operative tax conclusion must be based on the enacted statutory text and the notification bringing the amendment into force.

17. Construction and HAM projects — detailed application

Section 13 is particularly important for construction and infrastructure businesses because the commercial billing process often includes measurement, certification, RA bills, milestone payments, retention, mobilisation arrangements and long payment cycles.

Typical project sequence

Project event	Tax question	Evidence
Work executed	When was the service provided?	Measurement book, site records, engineer certification
Milestone completed	Does the contract link payment/invoicing to the event?	Work order, concession agreement, milestone certificate
RA bill prepared	When is the invoice legally required?	RA bill, invoice, Section 31 analysis
Client certification delayed	Does certification delay alter the statutory invoice/time-of-supply point?	Correspondence and contract clauses
Payment received months later	Does the payment date become the earlier Section 13 trigger?	Bank statement and ledger
Long-term HAM arrangement	Is the arrangement a continuous supply of services and what events trigger invoicing?	HAM agreement, payment schedule, Section 31(5) analysis

CBIC has specifically addressed construction situations where invoice verification by engineers is delayed and states that the statutory time-of-supply provisions continue to apply. More recently, the GST Council examined HAM contracts and described the construction and O&M arrangement as a continuous supply of services for the time-of-supply analysis. citeturn0search0turn2search0

Practical conclusion for infrastructure companies: The tax team should maintain a contract-level time-of-supply matrix for every major project instead of determining GST only from the date on which the customer finally pays the RA bill.

18. Detailed practical examples

Example 1 — normal consultancy invoice issued on time

Consultancy service is completed on 5 April. Invoice is issued on 20 April within the prescribed period. Payment is received on 30 May. Section 13(2)(a) compares invoice date and payment date. The earlier date is the time of supply.

Example 2 — invoice issued late

Service is provided on 5 April, but the supplier fails to issue the invoice within the statutory period and eventually issues it on 20 June. Section 13(2)(b) becomes relevant and the date of provision of service is compared with receipt of payment.

Example 3 — advance for professional service

A client pays an advance on 1 April for services to be performed in June. The payment trigger under Section 13(2) must be considered. The fact that the final service will be completed later does not by itself remove the advance from the time-of-supply analysis.

Example 4 — RCM payment before 60 days

A supplier issues an RCM-service invoice on 1 April. The recipient records payment on 20 April. The payment trigger can arise earlier than the 60-day invoice trigger, so the earlier date controls.

Example 5 — RCM supplier invoice, no payment

Supplier issues an invoice on 1 April and the recipient does not pay for months. The 60-day trigger remains relevant; non-payment does not indefinitely postpone the RCM time of supply.

Example 6 — recipient-issued RCM invoice

Where the law requires the recipient to issue the invoice, the post-1 November 2024 Section 13(3)(c) rule makes the recipient's invoice date an express trigger. This must be compared with the other applicable Section 13(3) triggers.

Example 7 — overseas associated enterprise

Indian recipient books a management-service cost on 31 March and pays the overseas associated enterprise on 30 June. The special associated-enterprise rule can make the 31 March book-entry date the earlier time of supply.

Example 8 — delayed interest

Customer pays the original service invoice but later pays contractual interest for delayed payment. The additional amount has its own Section 13(6) time-of-supply event when received.

Example 9 — voucher transaction before 1 October 2025

For an older voucher transaction, the historical Section 13(4) rule may need to be examined. For a 2026 transaction, the omitted voucher sub-section cannot be treated as current law.

19. Professional Section 13 workflow

1. Identify the service
Describe the actual supply, not merely the invoice narration.

2. Determine charge mechanism
Forward charge or reverse charge?

3. Identify supply date
When was the service actually provided?

4. Determine invoice deadline
Read Section 31 and applicable rules for the service.

5. Check actual invoice date
Was the invoice issued within the prescribed period?

6. Check payment
Book-entry date and bank-credit/debit evidence.

7. Check special rules
Continuous supply, associated enterprise, RCM, recipient invoice.

8. Check historical law
Especially for transactions before 1 November 2024 or 1 October 2025.

9. Determine tax period
Document the earliest applicable statutory trigger.

10. Reconcile
Books → invoice → GSTR-1 → GSTR-3B → payment ledger.

20. Audit documentation — what should be retained?

Document	Purpose
Contract / work order	Establishes service obligations, milestones and payment terms.
Service completion evidence	Supports actual provision of service.
Invoice	Establishes actual invoice date and description.
Invoice due-date working	Shows whether Section 31 period was complied with.
Bank statement	Supports payment date.
General ledger	Supports book-entry date and accounting treatment.
RA bills / measurement books	Critical for construction and infrastructure services.
RCM register	Tracks 60-day dates, payment dates and self-invoices.
Associated-enterprise reconciliation	Tracks book entries and payments for cross-border related-party services.
Tax memo	Explains the legal conclusion for material or disputed transactions.

Audit-ready principle: A reviewer should be able to reconstruct the Section 13 conclusion from the file without asking the accounts team to recreate the history years later.

21. Common mistakes

Assuming GST becomes payable only when the customer pays.
Ignoring the statutory invoice deadline under Section 31.
Using the actual invoice date without checking whether the invoice was issued on time.
Applying Section 13(2) to an RCM service.
Using the old two-trigger RCM rule for transactions after 1 November 2024 without considering recipient-issued invoices.
Failing to compare the payment book-entry date with the bank date.
Ignoring advances for services.
Treating delayed client certification as automatically postponing GST.
Ignoring associated-enterprise book entries for imported services.
Applying the historical voucher rule to transactions after 1 October 2025.
Failing to preserve historical statutory versions when reviewing old periods.
Using a GST Council recommendation as the operative law without checking the enacted amendment and effective date.

22. Related provisions to read with Section 13

Provision	Why it matters
Section 9	Charging provision; establishes the levy and reverse-charge framework.
Section 11	Exemption may remove the tax liability before timing becomes relevant.
Section 12	Time of supply for goods; useful for distinguishing goods and services.
Section 14	Special time-of-supply rules where GST rate changes.
Section 15	Determines value of supply and additional amounts.
Section 31	Invoice timing directly feeds the Section 13(2) test.
Section 34	Credit/debit notes can affect later adjustments.
Rule 47	General service invoice timing and specified extensions.
Rule 47A	Relevant to invoice timing for specified RCM situations introduced with the 2024 amendments.
IGST Act Section 13	Separate provision with the same section number dealing with place of supply of cross-border services; do not confuse it with CGST Section 13.

Important naming point: “Section 13” exists in both the CGST Act and the IGST Act, but they deal with different subjects. This page concerns Section 13 of the CGST Act — Time of Supply of Services. The IGST Act's Section 13 concerns place of supply of services where supplier or recipient is outside India.

23. Key takeaways

Section 13 determines when GST liability arises on services.
Normal services use an invoice/payment/provision-of-service sequence.
Section 31 must be read together with Section 13 because the invoice deadline determines which Section 13(2) branch applies.
Advances for services can trigger GST under the payment rule.
RCM has a separate timing mechanism, including the 60-day supplier-invoice rule.
From 1 November 2024, recipient-issued invoices have their own Section 13(3)(c) trigger.
Associated-enterprise services from outside India have a special book-entry/payment rule.
The voucher-specific Section 13(4) provision is no longer operative from 1 October 2025.
Interest, late fee and penalty for delayed payment have a separate timing rule.
For construction and infrastructure projects, contract milestones, RA bills, certification and payment records should be mapped to Section 13.

Disclaimer: This guide is for practical knowledge and working guidance. GST law, notifications, circulars, rules, rates, judicial decisions and portal processes can change. Historical transactions should be tested against the law and subordinate legislation applicable to the relevant date. Material or disputed positions should be independently reviewed.