Indirect Tax Laws · Tax Invoice, Credit and Debit Notes

Tax Invoice under GST: Time Limits and Contents

Updated 5 October 2026 · Fact-checked

A tax invoice is the document a registered supplier issues for a taxable supply of goods or services. For goods, issue it at or before removal or delivery. For services, issue it within 45 days of supply (30 days for banks, insurers and NBFCs). Check the time limit, the Rule 46 particulars, and whether a bill of supply applies.

Understand Tax Invoice: Time Limits and Contents

A tax invoice is the main proof of a taxable supply under GST. It tells the recipient how much tax was charged. It also supports the recipient's input tax credit claim and the supplier's outward supply reporting. Section 31 of the CGST Act and Rules 46 to 55 deal with it.

The duty falls on a registered person making a taxable supply. An unregistered person cannot issue a tax invoice. A registered person who pays tax under the composition scheme, or who makes only exempt supplies, does not issue a tax invoice. Such a person issues a bill of supply, which carries no tax (Rule 49). Under Section 31(4), a registered person who supplies both taxable and exempt goods or services to an unregistered person may issue a single invoice-cum-bill of supply for all such supplies.

The time limit depends on what you supply. For goods that move, the invoice is due before or at the time of removal. For goods that do not move, it is due at or before delivery or when the goods are made available to the recipient. For services, the invoice is due within the prescribed period from the date of supply. That period is 45 days, or 30 days for an insurer, banking company, financial institution or NBFC. Continuous supplies and goods sent on approval have their own timing rules.

An invoice must carry the particulars prescribed in Rule 46, such as supplier details, a unique serial number, date, recipient details, HSN or accounting code, description, taxable value, rate and amount of tax, and place of supply. Some taxpayers must also issue e-invoices. They report the invoice to the Invoice Registration Portal, which returns an Invoice Reference Number (IRN) and a QR code. A receipt voucher is issued when an advance is received against a supply of services.

Questions usually give a short case and ask one of three things: by when to issue the invoice, what it must contain, or which document applies. Answer in that order.

Key rules to remember

Goods involving movement: Invoice date ≤ date of removal of goods; Issue the invoice before or at the time of removal for supply to the recipient.
Goods not involving movement: Invoice date ≤ date of delivery or making goods available; The invoice is due at or before the time the goods are delivered or made available to the recipient.
Services (general): Invoice date ≤ date of supply + 45 days; Rule 47. Count from the date of supply of service.
Services by insurer, banking company, financial institution or NBFC: Invoice date ≤ date of supply + 30 days; Shorter period under Rule 47 for these suppliers.
Continuous supply of goods: Successive statements of accounts: invoice before or at the time each statement is issued. Successive payments: invoice before or at the time each payment is received.; Applies where goods are supplied continuously and successive statements of accounts or successive payments are involved.
Continuous supply of services: Due date known: on or before due date. Due date not known: on or before receipt of payment. Payment tied to an event: on or before completion of the event.; If the supply ceases before completion, issue the invoice at the time of cessation, to the extent supplied. A continuous supply of services runs for more than three months under a contract with periodic payment obligations.
Goods sent on approval (sale or return): Invoice date ≤ earlier of (date supply takes place, 6 months from removal); Applies where goods are removed before the supply takes place.
Rule 46 key particulars: Supplier name, address, GSTIN | serial number (max 16 characters, unique for the financial year) | date | recipient details | HSN or SAC | description | quantity and unit (goods) | total value | taxable value after discount | rate and amount of CGST, SGST/UTGST, IGST, cess | place of supply (with state name for inter-State) | delivery address if different | reverse charge indicator | signature or digital signature of the supplier or authorised representative; For an unregistered recipient, name, address and delivery address with state name and code are required where the invoice value is ₹50,000 or more. The number of digits of the HSN code you must show depends on the supplier's aggregate turnover: 4 digits up to ₹5 crore and 6 digits above ₹5 crore, as notified. Check the current notification.
Copies of invoice: Goods: original (recipient), duplicate (transporter), triplicate (supplier). Services: original and duplicate.; Rule 48. For e-invoiced supplies, the IRN and QR code apply.
Bill of supply: Issued by composition taxpayer or supplier of exempt goods or services in place of tax invoice; Rule 49. It shows no tax. A composition taxpayer cannot charge tax. Section 31(4) allows a single invoice-cum-bill of supply for taxable and exempt supplies to an unregistered person.
E-invoicing threshold: Aggregate turnover exceeds ₹5 crore in any preceding financial year from 2017-18; Notified persons only. Certain classes, such as SEZ units and banks, insurers and NBFCs, are exempt. Check the current notification for reporting time limits for large taxpayers.

How to solve Tax Invoice: Time Limits and Contents questions

Use this order for any case on tax invoices. It stops you from mixing up the supplier's status, the type of supply and the time limit.

1Identify the supplier's status. Ask: is the supplier registered, and is it a composition taxpayer or an exempt-only supplier? An unregistered supplier issues no tax invoice. A composition taxpayer or exempt supplier issues a bill of supply.
2Identify the supply: goods or services, and whether it is one-time, continuous, or on approval. Write the category in one line.
3Apply the matching time rule. For goods, check whether they move. For services, use 45 days, or 30 days for banks, insurers and NBFCs. For continuous supply, use the due date, payment or event rule.
4Count the days exactly. The date of supply is day zero. Show the arithmetic with month-end dates.
5Check the particulars if the question asks about contents. List the Rule 46 items relevant to the facts, such as place of supply for inter-State supplies and delivery address for unregistered recipients of ₹50,000 or more.
6Check special documents. If an advance is received for services, a receipt voucher applies. If the recipient pays tax under reverse charge, the recipient issues the invoice or payment voucher.
7Check e-invoicing. If aggregate turnover exceeds ₹5 crore and the supplier is not in an exempt class, the invoice must carry an IRN and QR code.
8Write the conclusion in provision-facts-conclusion form: the rule, the facts applied, the final due date or document.

Quickest way: Three-question check

When to use it: Use this for MCQs and for short parts of written answers when you have about two minutes.

Question 1: Who is the supplier? Registered and regular means tax invoice. Composition or exempt-only means bill of supply.
Question 2: What is the supply? Goods mean removal or delivery. Services mean 45 days (30 days for financial institutions). Continuous supply means the due-date, payment or event rule.
Question 3: Is there a special trigger? Advance for services means receipt voucher. Reverse charge means a self-invoice or payment voucher. Turnover above ₹5 crore means e-invoice.
For date arithmetic, count the days left in the month, then add the remainder.

Common mistakes in Tax Invoice: Time Limits and Contents

Applying the 45-day limit to goods.
Students remember '45 days' as the general invoice limit.
Fix: The 45 days applies only to services. For goods, the invoice is due at or before removal or delivery.
Forgetting the 30-day limit for banks, insurers, financial institutions and NBFCs.
The exception is mentioned in only one line of the rule.
Fix: Check the supplier's nature first. If it is a financial services provider, use 30 days.
Telling a composition dealer to issue a tax invoice.
Students treat every registered person alike.
Fix: A composition taxpayer issues a bill of supply and cannot collect tax. The same applies to a supplier making only exempt supplies.
Using the wrong trigger for continuous supply of services.
The three cases look similar.
Fix: Ask whether the due date is known, unknown, or tied to an event. Then pick: due date, receipt of payment, or completion of the event.
Listing particulars from memory without linking them to facts.
Students recite Rule 46 in full and miss what the case needs.
Fix: Pick the items the facts trigger, such as place of supply for inter-State supplies, reverse charge indicator, and recipient details for unregistered buyers above ₹50,000.
Assuming all taxpayers need e-invoices.
E-invoicing is widely discussed, so students overgeneralise it.
Fix: State the aggregate turnover test (over ₹5 crore), and mention exempt classes. Smaller taxpayers issue ordinary invoices.

Worked examples

Example 1

Meridian Consultants Pvt Ltd, a registered company, completed an advisory assignment for a client on 12 June 2026. Its subsidiary, Meridian Finance Ltd, an NBFC, also provided a loan processing service to a client on 12 June 2026. By what dates must each issue the tax invoice? Consider no continuous supply.

Show the solution

Provision: for supply of services, the invoice must be issued within 45 days from the date of supply. For an insurer, banking company, financial institution or NBFC, the period is 30 days.
Meridian Consultants: date of supply is 12 June 2026. Days left in June after 12 June: 30 − 12 = 18. Remaining days: 45 − 18 = 27. So the due date is 27 July 2026.
Meridian Finance (NBFC): 30 days applies. Days left in June: 18. Remaining days: 30 − 18 = 12. So the due date is 12 July 2026.
Conclusion: apply the 45-day limit to the consultant and the 30-day limit to the NBFC.

Answer: Meridian Consultants must issue its invoice by 27 July 2026. Meridian Finance (NBFC) must issue its invoice by 12 July 2026.

Example 2

Harbour Facility Services Ltd, a registered supplier, provides housekeeping services to a corporate client under a 12-month contract starting 1 April 2026. The contract says the monthly bill is payable on the 10th of the following month. Separately, Harbour builds a custom machine for another customer. The customer will pay ₹4,00,000 on completion of final testing, which is completed on 20 September 2026. Harbour dispatches the machine to the customer's factory by its own truck on 22 September 2026. State the time for invoicing the housekeeping bill for April 2026 and the time for invoicing the machine, and say which document applies if Harbour receives an advance of ₹1,00,000 for the housekeeping service before 1 April 2026, and how that advance is dealt with in the invoice.

Show the solution

Housekeeping is a continuous supply of services: it runs for more than three months under a contract with periodic payment obligations.
The due date of payment is fixed in the contract, so the invoice must be issued on or before the due date. For April 2026, the due date is 10 May 2026.
The machine is a supply of goods, not services. The continuous supply of services event rule therefore does not apply, even though payment is linked to final testing.
The machine moves to the customer, so the invoice must be issued at or before the time of removal. Removal is on 22 September 2026, so the invoice is due on or before 22 September 2026.
The testing date of 20 September 2026 only fixes when payment falls due. It is not the trigger for the invoice.
For the advance of ₹1,00,000 received for a supply of services, Harbour issues a receipt voucher at the time of receiving the advance.
When Harbour issues the housekeeping invoice, the advance already received is adjusted against it, to the extent it covers that bill. The invoice refers to the receipt voucher and shows only the balance payable by the client.
Conclusion: the April invoice is due by 10 May 2026, the machine invoice is due on or before 22 September 2026, and the receipt voucher is issued on receipt of the advance and referenced in the invoice that adjusts it.

Answer: The April 2026 housekeeping invoice is due on or before 10 May 2026. The machine is goods that move, so its invoice is due on or before removal on 22 September 2026, not by reference to the 20 September 2026 testing date. A receipt voucher is issued when the ₹1,00,000 advance for housekeeping is received. The invoice then adjusts that advance, refers to the receipt voucher and shows only the balance payable.

Exam tips

Write the rule first, then apply the facts, then conclude. Examiners give marks for each step.
Show date arithmetic in full. State the day count and the month-end dates so a wrong final date can still earn step marks.
In MCQs on time limits, check the supplier type first. The 30-day exception for financial services is a common trap.
When a question mentions a composition dealer or exempt supplier, name the bill of supply and say that no tax is charged.
For e-invoicing questions, state the turnover test, say that notified exempt classes exist, and mention the IRN and QR code.

Practice questions from Tax Invoice, Credit and Debit Notes

Tax Invoice: Time Limits and Contents in other exams

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

Tax Invoice: Time Limits and Contents: frequently asked questions

What is the time limit for issuing a tax invoice for services under GST?

A registered supplier must issue the invoice within 45 days of the date of supply of services. If the supplier is an insurer, banking company, financial institution or NBFC, the limit is 30 days. For continuous supply of services, the due date, payment or event rule applies.

What is the difference between a tax invoice and a bill of supply?

A tax invoice is issued by a registered person for a taxable supply and shows the tax charged. A bill of supply is issued by a composition taxpayer or a supplier of exempt goods or services and shows no tax. Under Section 31(4), a registered person supplying both taxable and exempt goods or services to an unregistered person may issue a single invoice-cum-bill of supply for all such supplies.

How is an invoice issued for continuous supply of services?

If the due date of payment is fixed in the contract, issue the invoice on or before that date. If the due date is not fixed, issue it on or before the supplier receives payment. If payment depends on completion of an event, issue it on or before completion of the event.

Who must issue e-invoices?

Notified registered persons whose aggregate turnover exceeds ₹5 crore in any preceding financial year from 2017-18 must issue e-invoices. They report the invoice to the Invoice Registration Portal and obtain an IRN and QR code. Certain classes, such as SEZ units and banks, insurers and NBFCs, are exempt, so check the current notification.