GST Input Tax Credit Reversal: Rule 37, 42, 43 & Blocked Credits

Understand when GST input tax credit may require reversal, how to document it, and how to reconcile purchase records with GSTR-2B and GSTR-3B.

What is an ITC reversal?

Input tax credit (ITC) is available only subject to the requirements of GST law. A reversal removes or adjusts credit that is not presently eligible or must be apportioned. It is different from merely finding an invoice absent from GSTR-2B: mismatches first require verification and classification.

Key scenarios to review

1. Rule 37 — non-payment to supplier. Subject to the applicable exceptions, ITC may need reversal when payment of invoice value and tax is not made within the stipulated 180 days. Re-availment may be possible after payment, subject to the applicable conditions.
2. Rules 42 and 43 — mixed use. Common inputs/input services and capital goods used for exempt or non-business purposes may require allocation and reversal calculations under the prescribed method.
3. Section 17(5) — blocked credits. Certain expenditures have statutory restrictions, with exceptions depending on facts and use.
4. Credit notes and supplier corrections. Evaluate the recipient’s actual credit position, credit-note reporting and Invoice Management System (IMS) status where relevant.
5. Other ineligible or temporary credit. Examine statutory conditions, GST portal reporting and the nature of any reclaimable reversals.

Monthly ITC reconciliation workflow

1. Export the purchase register and GSTR-2B for the period.
2. Match GSTIN, invoice number/date, taxable value and IGST/CGST/SGST amounts.
3. Flag unmatched, duplicate and amended invoices for investigation.
4. Classify eligible, ineligible, temporarily reversible and reclaimable credit separately.
5. Maintain a supplier-payment aging report for potential Rule 37 reversals.
6. Calculate exempt/non-business attribution for common inputs and capital goods when applicable.
7. Review credit notes and IMS decisions, including partial reversal functionality where relevant.
8. Reconcile the ITC ledger and applicable GSTR-3B reporting tables.
9. Retain evidence for any later re-availment, including supplier payments and reconciliations.

Illustrative reversal register

Important filing caveat

The exact return-table treatment, interest consequences and reclaimability depend on the statutory provision and current GST portal reporting instructions. Do not automatically classify every difference in GSTR-2B as a permanent ITC reversal. Reconcile invoices and evaluate conditions first.

Related guidance

Read the GST compliance guide, GSTR-1 vs GSTR-3B reconciliation checklist, GST invoicing guide and month-end accounting controls.

Practical ITC reversal example

Example: Assume ITC originally availed was ₹18,000. Where a reversal condition is established and applies to the whole amount, entering ₹18,000 as reversal gives a balance of ₹0 in the Excel sheet. Check the legal position separately, and do not re-avail credit without meeting the applicable conditions.

1. Download GSTR-2B and export the purchase register for the correct period.
2. Compare GSTIN, invoice details and credit tax heads; investigate mismatches.
3. Check Rule 37, Rules 42/43 and section 17(5) as applicable.
4. Record any reversal, return period and reclaim evidence in the ITC Reversal sheet.

Official portal guidance: GSTR-2B viewing/download and summary instructions; CBIC input tax credit rules. These are official references, not live screenshots from an account.

Official references

CBIC input tax credit rules · GSTN IMS credit-note FAQ.

Last reviewed: 28 September 2026 · By TaxNexus Editorial Team · Educational information; check current GST notifications and consult a qualified professional for transaction-specific advice.