A GST debit note is the document a registered shop issues to increase the value and tax of a bill it already raised — most often when it undercharged, revised a price upward, or short-billed the quantity. The supplier issues it (not the buyer), it must point back to the original invoice, and once declared in your GST return it raises your output tax. This guide covers when to issue one, the GST debit note format a small shop should follow, whether there is a deadline, and a worked example you can copy.
Debit note vs credit note — the one-line difference
If you have read our GST credit note format guide, a debit note is its mirror image:
- A credit note reduces a bill — a customer returns goods, or you overcharged.
- A debit note increases a bill — you undercharged, the price was revised up, or you short-billed the quantity.
Both are governed by Section 34 of the CGST Act and both carry almost the same fields. The direction of the money is what differs (see the rules on cbic.gov.in).
Two things people call a “debit note”
This is where small shops get confused, so it is worth being clear up front. The words “debit note” get used for two different documents:
- The GST (Section 34) debit note — you, the seller, raise it to charge a customer more than the original invoice. This is the one that has a GST format and increases your output tax. It is what the rest of this guide is about.
- A purchase-return debit note — the note a shop raises against its own supplier when it sends goods back. Here you are the buyer, not the seller. Under GST it is usually the supplier who then issues a credit note for that return; your debit note is the commercial record of it on the buying side.
Keep the two apart and everything else is simple.
When to issue a GST debit note
Under Section 34(3) of the CGST Act, a registered supplier issues a debit note when the taxable value or the tax charged on the original invoice was less than it should have been. In a small shop that usually means one of:
- You undercharged — the rate on the bill was lower than agreed, or a wrong (lower) tax rate was applied.
- The price was revised up after billing — a rate increase the customer agreed to.
- You short-billed the quantity — the bill missed an item or a few units that were actually supplied.
A debit note always adds to what was billed. If instead you need to charge the customer less (an overcharge or a return), that is a credit note, not a debit note.
What a GST debit note must contain
The format follows the CGST Rules and mirrors a tax invoice. A compliant debit note carries these fields — confirm the current list on cbic.gov.in or with your CA:
| # | Field | Notes for a small shop |
|---|---|---|
| 1 | Your shop’s name, address & GSTIN | Same header as your invoice. |
| 2 | The words “Debit Note” | So the document type is clear. |
| 3 | A serial number | Consecutive, unique for the financial year, up to 16 characters — keep it in its own series. |
| 4 | Date of issue | DD/MM/YYYY. |
| 5 | Customer’s name, address & GSTIN | GSTIN if the buyer is registered; state code if not. |
| 6 | Original invoice number & date | The bill you are correcting. |
| 7 | Value added & tax | The extra taxable value, plus CGST + SGST or IGST. |
| 8 | Signature | Physical or digital signature of the supplier. |
Keeping your debit notes in their own neat, gap-free number series — separate from your invoices and credit notes — makes reconciliation at return time far easier. Our guide to the GST invoice number format for the financial year explains the numbering rules the same way.
The tax split works exactly like an invoice
A debit note is not a special tax animal. It carries the same GST rate and the same split as the original sale:
- Same-state (intra-state) sale: the tax splits into CGST + SGST, each at half the rate — so the debit note adds CGST + SGST too.
- Other-state (inter-state) sale: the original bill charged a single IGST, so the debit note adds IGST.
If you are shaky on which one applies, our CGST, SGST and IGST guide walks through it with examples.
A worked example: an undercharge in Ludhiana
Karan runs a hardware shop in Ludhiana, Punjab. Last week he sold 20 door hinges to a local contractor — a registered buyer in the same state, so an intra-state sale at 18% GST (confirm the current rate for your goods on cbic.gov.in).
His original invoice billed the hinges at ₹250 each:
- Taxable value: 20 × ₹250 = ₹5,000
- CGST 9% = ₹450, SGST 9% = ₹450
- Invoice total = ₹5,900
A few days later both sides confirm the agreed rate was actually ₹300, not ₹250 — Karan undercharged ₹50 per hinge. The shortfall in taxable value is 20 × ₹50 = ₹1,000. He raises a debit note against that invoice for the difference only:
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KARAN HARDWARE GSTIN: 03ABCDE1234F1Z5
Gill Road, Ludhiana, Punjab - 141003
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Debit Note No: DN2026-27/0004 Date: 20/08/2026
Against invoice: INV2026-27/0231 (12/08/2026)
Customer: Singh Contractors GSTIN: 03PQRST5678G1Z9
Place of supply: Punjab (03)
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Item Qty Rate diff Taxable GST
Door hinge 20 50.00 1,000.00 18%
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Additional taxable value: 1,000.00
CGST 9%: 90.00
SGST 9%: 90.00
TOTAL DEBITED: ₹ 1,180.00
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Check the maths: additional taxable ₹1,000 × 9% = ₹90 CGST and ₹90 SGST, so ₹1,000 + ₹90 + ₹90 = ₹1,180. The contractor pays the extra ₹1,180, and when Karan reports this debit note his output tax for the period goes up by ₹180 (₹90 CGST + ₹90 SGST). Only the difference goes on the debit note — never the whole bill again.
Is there a deadline to issue a debit note?
Unlike a credit note, a GST debit note has no fixed cut-off to issue. That is because a debit note increases tax rather than reducing it, so there is no revenue risk to the government in issuing it later. You simply declare it in the return for the month you issue it, and your output tax rises accordingly.
There is a related rule on the buyer’s side: a registered customer can claim input tax credit on your debit note, but that claim has its own time window tied to the debit note’s date. If you sell to businesses, it is worth telling the buyer promptly. The exact rule changes from time to time, so confirm the current position on gst.gov.in or with your CA.
Where Yojika fits
Yojika is offline-first GST billing software for Indian small shops, and it keeps the return side of your books clean. When goods move back, you raise a note instead of a bill:
- a credit note for a sales return (a customer returns something you sold), and
- a debit note for a purchase return (you send goods back to your supplier),
each on its own gap-free number series, with the CGST/SGST or IGST split and the nearest-rupee rounding worked out for you, ready to print to A4, A5, or a thermal receipt in any of the 22 official Indian languages — and your data stays on your own PC.
A quick, honest note on scope: Yojika does not file your GST returns, and today its debit-note screen is for purchase returns on the buying side, not for issuing a Section 34 debit note to a customer. For a customer correction, the numbering and format discipline in this guide is what your CA or accountant will follow.
- See what’s included on the features page.
- Check simple, transparent pricing.
- Or download Yojika and try it free for 14 days.
New to GST bills in general? Start with our GST invoice format for small shops, and read the companion GST credit note format guide for the other direction.
This article is general information, not tax advice. GST rules, rates and deadlines change — confirm the current position on gst.gov.in or cbic.gov.in, or with your CA.