In This Article
The Core Difference
Output Tax Mismatch
- Rule: Rule 88C, CGST Rules 2017
- Triggered when: GSTR-1 turnover > GSTR-3B turnover by more than ₹25 lakh or 20%
- Department's concern: You declared higher sales to your customers than you paid tax on
- If ignored: GSTR-1 filing is blocked
- Deadline: 7 days
Input Tax Credit Mismatch
- Rule: Rule 88D, CGST Rules 2017
- Triggered when: ITC in GSTR-3B > ITC in GSTR-2B by more than ₹25 lakh or 20%
- Department's concern: You claimed more ITC than your suppliers have filed
- If ignored: Excess ITC is blocked in GSTR-3B
- Deadline: 7 days
They look similar on the surface — both are auto-generated, both give you just 7 days to respond, and both can block your next return if ignored. But the underlying question is different: DRC-01B asks "why does your output tax not match your declared sales," while DRC-01C asks "why does your input credit not match what your suppliers have filed."
Side-by-Side Comparison
| Feature | DRC-01B | DRC-01C |
|---|---|---|
| Legal basis | Rule 88C, CGST Rules 2017 | Rule 88D, CGST Rules 2017 |
| What is compared | GSTR-1 vs GSTR-3B (output tax) | GSTR-3B vs GSTR-2B (input ITC) |
| Threshold for notice | Excess > ₹25 lakh or 20% of GSTR-3B tax, whichever is lower | Excess > ₹25 lakh or 20% of GSTR-2B ITC, whichever is lower |
| Penalty for no reply | GSTR-1 filing blocked | Excess ITC blocked in GSTR-3B |
| Reply involves | GSTR-1 vs 3B reconciliation or DRC-03 payment | Invoice-level ITC reconciliation against GSTR-2B |
| Deadline | 7 days from notice date | 7 days from notice date |
| Reply filed via | GST Portal — View Notices → Reply | GST Portal — View Notices → Reply |
Why GSTR-9 Season Makes This Worse
Annual return filing forces a full-year reconciliation that monthly or quarterly filings don't. Common, entirely legitimate reasons a mismatch surfaces at this point:
- Timing differences — a sale invoiced in March but only reflected in the following month's GSTR-3B
- Credit notes issued late in the year, adjusted in GSTR-1 but not yet reflected in GSTR-3B for the same period
- Supplier delays — your ITC claim was correct, but the supplier filed their GSTR-1 late, so it didn't show up in your GSTR-2B when you claimed it
- Amendments carried through GSTR-1A that haven't fully synced
None of these mean fraud or even an error on your part. But an unaddressed DRC-01B or DRC-01C doesn't care about intent — the blocking happens automatically regardless of whether the underlying reason was innocent.
⚠ Seven Days Is Shorter Than It Feels
Seven days moves fast when you're pulling reconciliation data from your accountant, cross-referencing invoices, and drafting a formal reply. Start the moment the notice arrives — don't wait until day 5.
What Each Reply Actually Needs
For DRC-01B
Your reply needs to reconcile GSTR-1 and GSTR-3B for the flagged period line by line, and either:
- Explain the timing or documentation reason for the gap (credit notes, amendments, late entries), or
- Pay the differential tax voluntarily via DRC-03 if the gap is genuine — and cite that payment in the reply
For DRC-01C
Your reply needs a GSTR-2B vs GSTR-3B ITC reconciliation, showing exactly which invoices account for the difference. Supplier-filed-late invoices are the most common legitimate explanation — support the ITC claimed with:
- Purchase invoices with date, GSTIN, and amount
- Bank statements confirming payment
- Supplier correspondence or GSTR-1 late-filing proof if available
In both cases, the reply format matters as much as the substance. Cite the correct rule (88C or 88D), address every line item flagged rather than giving a general explanation, and attach the reconciliation as a clearly labeled annexure.
Get Your DRC-01B or DRC-01C Reply in 30 Seconds
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📄 Generate Free Reply →Consequences of Ignoring
For DRC-01B: the GST system automatically blocks your GSTR-1 filing for subsequent periods. Your customers lose the ability to claim ITC on your invoices — which means your B2B buyers will start pressuring you to resolve the notice immediately.
For DRC-01C: the excess ITC amount is blocked in your GSTR-3B, meaning you cannot use it to offset your tax liability. If you had planned to use that ITC to reduce your cash outflow for the month, you'll now need to pay cash instead — a direct hit to working capital.
In both cases, the matter can escalate to a demand proceeding under Section 73 or 74 if the officer decides to act on the unresolved mismatch — so a 7-day notice can, if ignored, turn into a full demand with penalty.