GST DRC-01B: GSTR-1 vs GSTR-3B Mismatch Response Checklist

October 2026 update: gst drc 01b gstr1 vs gstr3b mismatch response checklist

Finin2min 2-minute summary

FORM GST DRC-01B is the system-driven mismatch control used when liability emerging from GSTR-1, GSTR-1A or IFF exceeds the tax reported in GSTR-3B beyond the prescribed system parameters. The notice is not merely an informational alert: the taxpayer must either discharge the difference or give a reasoned explanation within the Rule 88C workflow.

The first task is to identify whether the difference is real, timing-based or data-driven. Common causes include an invoice reported twice, a GSTR-1A correction not reflected in the return working, wrong tax-head mapping, an amendment belonging to another period, an e-invoice import issue, or a genuine short payment in GSTR-3B.

If the taxpayer does not address the intimation, the consequences can move beyond the original mismatch. Rule 59 filing restrictions can block subsequent GSTR-1/IFF filing, and unresolved differences can escalate into demand proceedings.

What exactly should be reconciled?

Build a three-way bridge: invoice register to GSTR-1/GSTR-1A, GSTR-1/GSTR-1A to GSTR-3B, and GSTR-3B to the electronic liability and cash/credit ledgers. Reconcile tax period, place of supply, tax head, debit/credit notes, amendments and advances. The control should explain both the taxable value and the tax difference, not only the net payable number.

Where GSTR-1A was used after GSTR-1 and before GSTR-3B, the amended figures must be included in the Rule 88C review. A team that compares only the original GSTR-1 with GSTR-3B can create a false exception after a valid same-period correction.

Pay or explain: choosing the correct path

Use the payment route where the short reporting in GSTR-3B is accepted. Map tax, interest and the correct period before making payment and preserve the challan/DRC evidence. Do not force a payment merely to remove the portal block if the difference has a defensible explanation.

Use the explanation route where the mismatch is supported by records. A strong response states the amount in dispute, the reason, the invoice or amendment trail, the correct tax period and the evidence attached. Vague statements such as “difference due to reconciliation” are weak because they do not let the officer or system reviewer reproduce the bridge.

Worked example

A company reports output tax of ₹12.40 lakh in GSTR-1 after a GSTR-1A addition, while GSTR-3B shows ₹11.90 lakh. The ₹50,000 difference is traced to an omitted debit note. If the company accepts the omission, it should compute the tax/interest consequence and use the permitted payment route. If the difference instead arose because a credit note was legally attributable to the same period but appeared differently in the portal extract, the response should document the credit note, return tables and tax-head bridge.

The important principle is that the response should resolve the legal and accounting cause of the mismatch, not just make the portal screen disappear.

Evidence file and controls

Keep the DRC-01B intimation, GSTR-1, GSTR-1A if any, GSTR-3B, invoice register, debit/credit note register, e-invoice reconciliation, ledger extracts, challan/payment proof and the final Part B response together. Add a maker-checker sign-off showing who validated the reason and amount.

Before the next GSTR-1 filing date, confirm that any filing restriction has actually cleared. If not, preserve screenshots/ARN and raise the issue through the portal support route rather than creating a second inconsistent response.

Common mistakes

Ignoring GSTR-1A; replying without invoice-level evidence; paying the gross difference when part of it is already corrected; using the wrong tax period; overlooking interest; and waiting until the next GSTR-1 is due to discover that the filing block is still active.

Finin2min takeaway

DRC-01B should be treated as a monthly close exception report. The fastest defensible response is produced when books, GSTR-1/GSTR-1A and GSTR-3B are already linked through a reproducible reconciliation with clear ownership for every unexplained difference.

Response drafting framework

A useful DRC-01B response starts with a one-line conclusion and then proves it. State whether the difference is accepted, partly accepted or disputed. Follow with a table showing portal amount, books amount, accepted amount, explained amount and evidence reference. Where the mismatch spans several invoices or tax heads, attach a schedule instead of writing a long narrative inside the portal text box. This approach makes later audit or adjudication review easier because the working paper can be reproduced without relying on memory.

For recurring causes, fix the upstream control. If the mismatch came from delayed ERP-to-GSP synchronisation, duplicate e-invoice imports or manual tax-head mapping, record the root cause and owner. DRC-01B should not become a monthly substitute for a broken GSTR-1-to-GSTR-3B close.

Questions finance teams should answer before submission

Can the exact portal difference be tied to identified documents? Has GSTR-1A been included? Does the explanation distinguish timing from permanent liability? If payment is proposed, is interest separately tested? Have credit notes and amendments been linked to the correct original invoice and period? Is the response supported by signed or system-generated records? Has the next return-filing block been checked? A yes/no checklist against these questions is more useful than a generic certification that “reconciliation has been completed”.

Final control point

One final control is to compare the response with the next month’s opening return data. If the team accepts liability in DRC-01B but leaves the ERP tax code or invoice status unchanged, the same document can reappear in later reconciliation. Close the loop by correcting the source record, updating the period bridge and documenting whether the adjustment belongs in a later return, a payment record or only the exception register. This prevents a one-time portal response from becoming a recurring accounting difference.