A GST credit note is the document you issue when you need to reduce the value or tax on an invoice you have already raised. If a customer returns goods, you charged too much, or a service was found deficient, you generally cannot just edit the old invoice. You issue a credit note under Section 34 of the CGST Act and report it in your GST return. Getting this right protects your tax liability and keeps your customer's input tax credit (ITC) in order.
This guide explains when to issue a GST credit note, what it must contain, the time limit that matters for FY 2025-26 sales, and a few habits that prevent mismatches.
When can you issue a GST credit note?
Section 34(1) allows a registered supplier to issue a credit note in situations such as these:
- Excess taxable value or tax: the invoice showed a higher taxable value or tax than what applied to the supply.
- Goods returned: the buyer sends back goods supplied to them.
- Goods or services not supplied or deficient: the supply turned out to be short, damaged or not as agreed.
- Post-sale price reduction: a discount or price reduction given after the supply, subject to the conditions in Section 15(3)(b) of the CGST Act. In simple terms, the discount should be backed by an agreement made before or at the time of supply and be linked to specific invoices.
If the invoice value was too low, the document is a debit note, not a credit note. Debit notes follow the same Section 34 framework.
What a credit note must contain
Rule 53 of the CGST Rules lists the particulars. In practice your credit note should show:
- The words "Credit Note" clearly on the document.
- Your name, address and GSTIN, and the recipient's name, address and GSTIN (or state details where the recipient is unregistered).
- A consecutive serial number, unique for the financial year, with letters, numerals and special characters limited to 16 characters.
- The date of issue.
- The number and date of the original invoice it relates to.
- Taxable value, rate of tax and the tax amount credited (CGST, SGST or IGST), along with HSN or SAC.
- Your signature or digital signature.
The structure is close to that of a tax invoice. If you want a refresher on the invoice fields, read our guide on the mandatory fields of a GST tax invoice under Rule 46.
The time limit: 30 November after the financial year
Under Section 34(2), a credit note that reduces your output tax liability must be declared in a return no later than 30 November following the end of the financial year in which the original supply was made, or the date of filing the relevant annual return, whichever is earlier. For supplies made in FY 2025-26, that date is 30 November 2026. Check the GST portal for any extension notified by CBIC before you rely on it.
This is why October and November are a good time to review old invoices. A credit note declared after the deadline may not reduce your tax liability, so you could end up paying GST on a sale that was effectively cancelled.
The ITC condition on the recipient's side
When a supplier issues a credit note, the recipient who took ITC on the original invoice is generally expected to reverse the corresponding credit. The proviso to Section 34(2) also says the supplier's reduction in liability applies only if the recipient has reversed the ITC, or has not availed it. Registered buyers should therefore watch for credit notes appearing in their GSTR-2B, and sellers should communicate credit notes to buyers promptly.
How credit notes are reported
Credit notes are reported in your GSTR-1 for the period in which you issue them. Registered-recipient credit notes go in the credit/debit note table of GSTR-1, while those for unregistered recipients are reported separately, with different treatment depending on the invoice value and the nature of the supply. Adjusted tax then flows into your GSTR-3B liability. If you file monthly, look at our GSTR-1 checklist for October 2026 before the 11 November due date. Always confirm the current table structure on the GST portal.
Common mistakes to avoid
- Issuing a credit note without referring to the original invoice. Mismatches then appear during reconciliation.
- Missing the 30 November cut-off. Create a reminder for old returns, discounts and customer settlements.
- Giving a discount informally. Without a prior agreement, a post-sale discount may not qualify as a reduction in the transaction value.
- Using a credit note when the invoice should be amended or cancelled. Where the issue is a wrong GSTIN or a wrong place of supply, the correction route differs, so take professional advice.
- Not telling the buyer. The buyer's ITC reversal depends on the document reaching them.
- Breaking the serial number sequence. Keep credit notes in their own consecutive series.
A simple monthly routine
- List all sales returns and price adjustments for the month.
- Match each to the original invoice number and date.
- Raise credit notes with the correct rate and HSN or SAC.
- Report them in that month's GSTR-1 and check that the liability in GSTR-3B reflects them.
- Reconcile at month-end, as part of your books close. Our half-year book closing checklist shows where this fits.
Key takeaways
- Issue a credit note under Section 34 when value or tax needs to go down after the invoice is raised.
- Follow Rule 53 for content, and link every credit note to its original invoice.
- For FY 2025-26 supplies, the statutory declaration cut-off is 30 November 2026 unless extended.
- Recipients should reverse ITC, so share the credit note promptly.
- Reconcile returns and discounts monthly, and confirm specifics with your CA.
If late fees on mistakes worry you, our explainer on GSTR-3B late fee and interest shows how costs add up. And if you keep your invoicing in AICOUNTLY Billing, use the checklist above as a monthly review of your own credit-note records. This article is general guidance, not legal advice.
