You issue a GST credit note when an invoice you already raised shows more value or more tax than it should. That happens when goods come back, when you agree a discount after the sale, or when you overbilled by mistake. The credit note has to quote the original invoice, use the same tax type and rate, and go out within the Section 34 time limit. Then your CA reports it in GSTR-1 and your output tax goes down.
That's the short answer. Let's go through each part slowly, the way your CA would explain it over chai.
When a credit note is the right tool (Section 34)#
Section 34 of the CGST Act lets a registered supplier issue a credit note in three situations:
- The taxable value or tax on the invoice is higher than it should be. Say you billed ₹1,20,000 when the agreed price was ₹1,00,000. Or you charged 18% where the correct rate was 12%.
- The buyer returned goods. A Surat textile trader sends 50 sarees to a Jaipur shop and 8 come back damaged.
- The goods or services were deficient. A Gurugram design agency delivers half a website and both sides agree to bill less.
Discounts after the sale need care. A post-sale discount reduces GST only when it was agreed before the supply (in a contract or scheme) and can be linked to specific invoices. The buyer also has to reverse the matching input tax credit. If you simply decide to give a loyal customer ₹5,000 off at year end, that is usually a "commercial" or "financial" credit note with no GST in it. Your sales value goes down in the books, but your GST does not.
When a fresh invoice or an amendment is better#
A credit note isn't always the answer. Use this as a quick guide:
| Situation | Better approach |
|---|---|
| Goods returned, price cut, overcharged tax | GST credit note |
| You undercharged (value or tax too low) | Debit note, not a credit note |
| Wrong buyer GSTIN, name or place of supply on an invoice already in GSTR-1 | Amend the invoice in a later GSTR-1 (amendment tables) |
| Charged CGST + SGST where IGST applied, or the other way round | Usually a full credit note and a fresh, correct invoice. Talk to your CA |
| Invoice raised but the supply never happened and it isn't reported yet | Cancel it before filing GSTR-1 |
| Discount not agreed before the sale | Commercial credit note without GST |
Here's a simple rule. If the transaction itself changed (return, lower price, less work done), use a credit note. If only the paperwork was wrong (wrong GSTIN, typo in the name), amend the invoice.
What every GST credit note must show#
The invoice rules (Rule 53 of the CGST Rules) list what a credit note must contain. Make sure yours has:
- Your name, address and GSTIN.
- The words "Credit Note" clearly marked as the type of document.
- A serial number from its own series, consecutive and unique for the financial year (for example CN/25-26/014). Keep it short. The rules cap the length, so check the current limit.
- Date of issue.
- The buyer's name, address and GSTIN if they're registered. For an unregistered buyer, give name, address, delivery address and state name and code where the rules require it.
- Serial number and date of the original invoice or invoices.
- Taxable value being reduced, the tax rate, and the tax amount credited, split into CGST, SGST/UTGST or IGST.
- Signature or digital signature of you or your authorised person.
Item 6 is the one people forget most. A credit note that isn't linked to an invoice is the most common reason a CA sends it back.
Linking it to the original invoice and getting the tax right#
Link it. Quote the original invoice number and date on every credit note. One credit note can cover more than one invoice to the same buyer. If you do that, list every invoice it adjusts.
Mirror the tax type. The credit note follows the original invoice:
- Intra-state sale (Delhi agency billing a Delhi client): credit note shows CGST + SGST, split equally.
- Inter-state sale (Pune manufacturer billing a Bengaluru retailer): credit note shows IGST.
Use the same rate. If the invoice charged 18%, the credit note reverses at 18%. Don't recalculate at a rate that applies today. The credit note corrects that one past supply.
Remember the buyer's side. Your output tax goes down only if the buyer hasn't passed the tax on, so the buyer has to reverse the ITC they claimed. For B2B credit notes, the buyer now sees them on the GST portal and can act on them there. If the buyer rejects or ignores a credit note, it can affect your adjustment, so check with your CA how this currently works.
E-invoicing. If e-invoicing applies to you, B2B credit notes also have to be reported to the Invoice Registration Portal, just like your invoices.
The time limit and how it goes into GSTR-1#
Time limit. Under Section 34, you have to declare a credit note in a return by the earlier of:
- 30 November after the end of the financial year in which the original supply happened, or
- the date you file your annual return for that year.
So for a sale made in FY 2024-25, the outer limit is 30 November 2025, or earlier if you file the annual return before then. Miss it and you can still issue a commercial credit note, but the GST won't come back. These dates have changed before, so confirm the current rule with your CA or on the GST portal.
GSTR-1 reporting. Your CA reports credit notes in GSTR-1 for the month or quarter you issue them:
- Registered buyers: in the credit/debit notes (registered) table, with the buyer's GSTIN, credit note number and date, and the tax amounts.
- Unregistered buyers: large inter-state B2C credit notes go in the credit/debit notes (unregistered) table. Smaller B2C adjustments are usually netted in the B2C (others) summary. Check the current value limit on the GST portal.
- Mistakes in an earlier credit note: fixed in the amendment table of a later GSTR-1.
Your CA's job is much easier with a clean list of every credit note: number, date, linked invoice, buyer GSTIN, place of supply, taxable value and the CGST/SGST/IGST split. In Clyrix, credit notes sit next to the invoices they adjust, and the GSTR-1 export your CA can use includes them. You can see how that works on GST invoicing.
A worked example#
Sharma Woodcraft, a furniture maker in Pune, Maharashtra, sells 100 chairs to a retailer in Bengaluru, Karnataka.
- Invoice INV/25-26/112, 10 June: taxable value ₹2,00,000, IGST 18% = ₹36,000, total ₹2,36,000.
On 2 July, the retailer returns 10 chairs with broken legs. Each chair was ₹2,000.
Sharma Woodcraft issues:
- Credit Note CN/25-26/007, 4 July
- Against: INV/25-26/112 dated 10 June
- Taxable value reduced: ₹20,000
- IGST @ 18%: ₹3,600
- Total credit: ₹23,600
It's IGST because the original sale was Maharashtra to Karnataka. The CA reports CN/25-26/007 in the July GSTR-1 under registered credit notes. Sharma's output IGST drops by ₹3,600. The Bengaluru retailer reverses ₹3,600 of ITC. The retailer's ledger now shows ₹2,12,400 due instead of ₹2,36,000.
If Sharma had sold to a retailer in Nashik instead, the same credit note would show CGST 9% (₹1,800) and SGST 9% (₹1,800).
Quick checklist before you send a credit note#
- The reason fits Section 34: return, overcharge, deficiency, or a discount agreed before the sale
- It isn't really a paperwork error that an invoice amendment would fix better
- Own serial number series, unique for the year
- "Credit Note" clearly marked, with the date of issue
- Buyer's name, address and GSTIN (if registered)
- Original invoice number(s) and date(s) quoted
- Same tax type (CGST+SGST or IGST) and same rate as the original invoice
- Taxable value and tax shown separately
- Signed or digitally signed
- Reported to the IRP if e-invoicing applies
- Within the time limit (30 November or the annual return date, whichever is earlier)
- Shared with your CA for this period's GSTR-1, and the buyer told so they can reverse ITC
Get these right and a credit note is a small, routine document. Skip the invoice link or the tax split, and it becomes a notice waiting to happen.
