CA Intermediate · Taxation

Time of Supply: CA Intermediate GST Chapter Guide

Time of supply is the point at which GST liability arises. Section 12 fixes it for goods and Section 13 for services. Decide whether the charge is forward or reverse, list the trigger dates (invoice, payment, receipt, books entry) and apply the section's rule. Then use Section 14 if the rate changed between these dates.

What this chapter covers

Time of supply answers one question: on what date does the liability to pay GST arise? The CGST Act, 2017 gives separate rules for goods (Section 12) and services (Section 13). Each section splits into forward charge, where the supplier pays tax, and reverse charge, where the recipient pays. Each also has special rules for vouchers, interest, late fees and cases the main rules do not cover.

Every rule works the same way. You are given a few dates: invoice date, date of supply or receipt, date of payment, date of entry in books. The section tells you which of these decides the time of supply, usually the earlier of two dates. The chapter is therefore a date-picking exercise. Practise it with timelines.

This chapter sits at the base of GST in Paper 3 Section B. The date you fix decides which tax period the supply falls in, which rate applies if the rate changed, and when interest starts. It links to value of supply, input tax credit, returns and payment of tax. Get it right here and those chapters become easier.

Time of supply gives steady marks in Section B because it suits both MCQs and short problems. An MCQ can test one date rule in a single line, and a written question can ask you to fix the date for several transactions in a table. The rules are fixed and mechanical, so you can score full marks if you learn the triggers precisely. A wrong date also carries into later answers on tax period, rate and interest, so an early slip costs marks twice.

Time of Supply: topics in the order to study them

1Time of Supply Basics and Section 12 OverviewStart here to learn what time of supply means, why it matters, and how Sections 12 and 13 fix it for goods and services, while Section 14 fixes it where the rate of tax changes.
2Time of Supply of Goods under Forward ChargeThis is the simplest rule: earlier of invoice date and payment date. It builds the habit of picking the earlier date.
3Time of Supply of Goods under Reverse ChargeIt adds more trigger dates, including the date immediately following 30 days from the supplier's invoice date, so study it after the forward-charge rule.
4Time of Supply of Services under Forward and Reverse ChargeServices have an invoice-within-time test and a 60-day reverse charge limit, so learn them after the goods rules to compare the two.
5Special Cases: Vouchers, Interest, Late Fee, Residual ProvisionsThese are exceptions to the main rules, so they come last, once you know the normal rule they depart from.

How to prepare Time of Supply

This chapter is about dates, so prepare with timelines rather than long notes. Build a clean comparison first, then drill with numbers.

Make a one-page chart with four rows: goods forward, goods reverse, services forward, services reverse. For each row, list the trigger dates and which one prevails.
Learn the invoice time limits: goods are invoiced at or before removal or delivery, and services within 30 days of supply (45 days for insurers, banks and NBFCs). Know the 30-day and 60-day reverse charge limits too.
Learn how the payment date is fixed. Forward charge: it is the earlier of the date the payment is entered in the supplier's books and the date it is credited to the supplier's bank account. Reverse charge: it is the earlier of the date of debit in the recipient's books and the date of debit in the recipient's bank account. Also know the small-excess-payment option in both Section 12(2) and Section 13(2): where the payment received exceeds the invoice value by up to ₹1,000, the supplier may, at its option, take the invoice date as the time of supply for that excess amount.
Solve every problem by drawing a timeline. Mark each date, label it, then apply the rule. Write the rule you used in one line before the answer.
Practise the special cases separately: vouchers, interest and late fee, and residual rules. Write each as a trigger sentence you can recall in one breath.
Solve MCQs under a time limit. Check the charge type first, then goods or services, then the dates. Attempt every MCQ, because there is no negative marking.
Revise Section 14, the time of supply provision for a change in the rate of tax. Its rules apply where the invoice, the payment and the supply fall on different sides of the rate change date. Practise the examples in your study material, since a date question often ends in a rate question.

Common mistakes in Time of Supply

Mixing up the goods and services rules, such as using the 30-day limit for services or the 60-day limit for goods.
Fix: Keep the comparison chart. Remember that goods reverse charge uses 30 days and services reverse charge uses 60 days.
Picking the later date when the rule says earlier, or the reverse.
Fix: Underline the words 'earlier' or 'earliest' in the rule, list all candidate dates, and then choose.
Using the cheque or invoice date as the payment date, or using the supplier's dates for a reverse charge payment.
Fix: For forward charge, use the earlier of the date of entry in the supplier's books and the date credited to the supplier's bank account. For reverse charge, use the earlier of the date of debit in the recipient's books and the date of debit in the recipient's bank account.
Applying the invoice-date rule for services without checking whether the invoice was issued within the allowed period.
Fix: First test the invoice against the 30-day (or 45-day) limit. If it was late, use the date of providing the service or the payment date, whichever is earlier.
Waiting for the invoice date when an advance payment has been received.
Fix: For both goods and services under forward charge, the date of receiving payment is itself a trigger date. Take the earlier of the invoice date and the payment date, so an advance received before the invoice fixes the time of supply at the payment date.
Writing only a date in the answer with no rule or reason.
Fix: Write the section, the charge type, the dates considered and the rule applied, then the final date. Step marks depend on this.

Last-day revision: Time of Supply

Section 12 covers time of supply of goods, Section 13 covers services, and Section 14 is the time of supply provision for a change in the rate of tax.
Goods, forward charge: earlier of invoice date (or the last date it should have been issued) and date of receiving payment. Advance payment is itself a trigger date.
Goods, reverse charge: earliest of receipt of goods, payment date, and the date immediately following 30 days from the date of the supplier's invoice.
If none of the reverse charge dates can be determined, the time of supply is the date of entry in the recipient's books.
Services, forward charge, invoice issued in time: earlier of invoice date and payment date. Advance payment is a trigger here too.
Services, forward charge, invoice not issued in time: earlier of date of providing the service and payment date.
Services, reverse charge: earlier of payment date and the date immediately following 60 days from the supplier's invoice date. If the invoice is not received or neither date can be determined, time of supply is the date of entry in the recipient's books.
Date of payment, forward charge: the earlier of the date of entry in the supplier's books and the date credited to the supplier's bank account. Reverse charge: the earlier of the date of debit in the recipient's books and the date of debit in the recipient's bank account.
Vouchers: time of supply is the date of issue if the supply is identifiable then, otherwise the date of redemption.
Interest, late fee or penalty for delayed payment: time of supply is the date the supplier receives it.
Residual goods rule (Section 12(5)): it applies only where the time of supply cannot be determined under the other provisions. Then, where a periodic return has to be filed, it is the due date of that return; in any other case, it is the date on which the tax is paid. Section 13 has a corresponding residual provision for services.
Always draw a timeline and name the rule before you write the date.

Time of Supply practice questions

Time of Supply in other exams

The same ground in other exams, if you are preparing for more than one or want another angle on it.

Time of Supply: frequently asked questions

Which sections of the CGST Act cover time of supply?

Section 12 covers goods and Section 13 covers services. Section 14 is the time of supply provision for a change in the rate of tax, and it applies where the invoice, the payment and the supply fall on different sides of the rate change date. Learn Sections 12 and 13 as parallel structures first, then Section 14.

Is time of supply the same as the date of invoice?

No. The invoice date is only one of the trigger dates. The law often takes the earlier of the invoice date and the payment date. In reverse charge and some service cases, other dates decide it.

How should I attempt a time of supply problem in the written paper?

Identify the supply as goods or services and the charge as forward or reverse. List all relevant dates on a timeline, state the rule, and pick the date. Write each step so you earn marks even if one date is wrong.

Do I need to memorise section sub-clause numbers?

Focus on the rules and the section numbers 12, 13 and 14 first. You score by applying the correct rule to the facts, not by quoting sub-clauses you are unsure of.