Debit note vs credit note under GST: rules + free generator

Quick frame: Credit notes and debit notes are how you legally adjust an already-raised tax invoice without canceling it. Section 34 of the CGST Act is the rulebook. Generate either with the Debit / Credit Note Generator.

Section 34 in plain English

	Credit Note (Sec 34(1))	Debit Note (Sec 34(3))
Issued by	Supplier	Supplier
When	Invoice value too high	Invoice value too low
Effect on supplier output GST	Decreases	Increases
Reasons	Goods returned, deficient supply, post-supply discount	Short-charged, additional supply
Time limit (for GST adjustment)	By 30 Nov of next FY or GSTR-9 filing, whichever earlier	No upper limit (but better to be timely)

When to issue a credit note

• Customer returned goods (defect, damage, wrong item).
• Service was deficient and a refund is due.
• Post-supply discount that was agreed in advance (Section 15 condition).
• Tax invoice was issued at wrong (higher) GST rate.

When to issue a debit note

• Original invoice missed an item.
• Original GST rate was lower than applicable.
• Subsequent rate revision (e.g., supplementary invoice).
• Foreign exchange variation in import-substitution items.

Mandatory contents (Rule 53)

Both notes must contain:

• "Credit Note" or "Debit Note" prominently
• Supplier name, address, GSTIN
• Serial number (independent series, continuous)
• Date of issue
• Recipient name, address, GSTIN (or address of unregistered recipient)
• Reference to the original tax invoice (number + date)
• Taxable value, GST rate, tax amounts being adjusted
• Signature

How it appears in GST returns

Suppliers report credit/debit notes in Table 9 of GSTR-1 (B2B credit/debit notes) or Table 9A/9C for B2C. The recipient's GSTR-2A and GSTR-2B reflect them automatically.

A buyer who has already claimed ITC on the original invoice must reverse the ITC for the amount of the credit note in their GSTR-3B.

The 30-November deadline (most missed)

To claim the GST reduction on a credit note, the supplier must:

• Issue the credit note before 30 November of the next financial year, AND
• Report it in GSTR-1 by the same deadline.

Miss this and you eat the GST. Common in March–April when teams scramble to close FY books.

Common mistakes

• Re-issuing the invoice instead of a credit note — illegal under GST. The original invoice still stands; you must use a note.
• Mixing credit and debit notes in one number series — keep two series (CN-…, DN-…).
• Post-supply discount without an agreement — Section 15(3)(b) requires the discount to be established in agreement, prior to supply. Otherwise, no GST reduction allowed.
• Forgetting to reverse buyer ITC — buyer's compliance, but supplier should communicate.

Related tools

• GST Invoice Generator
• Cash Receipt Generator — for the refund payment, if any.

Q. Can I issue a credit note without a corresponding tax invoice? A. No. Section 34 specifically requires reference to the underlying invoice.

Q. What if the customer is unregistered? A. Credit/debit notes work the same way. The supplier reduces output GST; there is no ITC reversal on the buyer side because they didn't claim any.