Credit Note under GST: When to Issue One, the Time Limit and the Format

Short answer: issue a credit note under section 34 of the CGST Act when an invoice overstated the value or the tax, when goods are returned, or when services were found deficient. It must be declared in a return no later than 30 November following the end of the financial year of the original supply, or the date you file the annual return, whichever is earlier. After that, you cannot reduce your output tax with it.

Tax rules, rates and thresholds change. This guide explains the general rules as published by the GST department (CBIC); confirm the current position with them or your adviser before relying on it.

When you can issue a credit note

• The taxable value or tax on the invoice was higher than it should have been.
• The customer returned goods.
• Goods or services supplied were found deficient.
• A discount agreed before or at the time of supply, and linked to the invoice, was given later.

The reverse case — you under-billed — needs a debit note, which raises the tax.

The deadline people miss

For an invoice from FY 2025-26, a credit note must be reported by 30 November 2026, or by the date you file the 2025-26 annual return if that comes first. Customers who ask for a correction late in the year often discover the window has closed and the only option is a commercial settlement outside GST.

What the credit note must show

• The words "Credit Note".
• Your name, address and GSTIN.
• A serial number, unique for the financial year, and the date.
• The customer's name, address and GSTIN (if registered).
• The number and date of the original tax invoice.
• The value of the goods or services, the tax rate and the tax being credited.
• Signature or digital signature.

One more rule: the customer must reverse the credit

Your output tax goes down only if the customer reduces their input tax credit by the same amount. Tell them when you issue the note, so their GSTR-2B and books agree with yours.

How this works in Grovia

Credit notes and debit notes are raised against the original invoice, so the original invoice is always referenced. They flow into your GSTR-1 and GSTR-3B working papers with the invoices. Grovia does not file the return for you.

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Frequently Asked Questions

What is the time limit for issuing a credit note under GST?

It must be declared in a return by 30 November following the end of the financial year of the original supply, or the date of filing the annual return for that year, whichever is earlier.

Is there a time limit for debit notes?

No deadline of that kind applies to debit notes; the input tax credit on them follows the general time limits for claiming credit.

Can one credit note cover several invoices?

Yes. A single credit note can be issued against multiple invoices to the same customer, as long as it references them.

Can I give a discount through a credit note?

Yes, if the discount was agreed before or at the time of supply and is linked to specific invoices. Other discounts are commercial credits and do not reduce GST.