A dispute under Rules 42 and 43 of the CGST Rules usually begins with a simple proposition: the taxpayer used inputs, input services or capital goods for a mix of taxable and exempt supplies. It becomes difficult when a notice assumes a common-credit figure, applies a ratio without examining the accounts, or demands reversal outside the formula prescribed by the Rules.
Section 17 of the CGST Act restricts credit to the extent attributable to taxable supplies and business use. Rule 42 deals with common input and input service credit. Rule 43 deals with common capital goods credit over the prescribed useful-life mechanism. A reply should therefore be a computation brief backed by records, not a general assertion that all purchases supported the business.
Build the correct credit map
Start by classifying credit into exclusive taxable-business credit, exclusive exempt or non-business credit, blocked credit, and genuinely common credit. For Rule 43, separately identify capital goods used exclusively for taxable supplies, exclusively for exempt or non-business purposes, and commonly used capital goods with acquisition dates and tax amounts.
The working papers should include electronic credit ledger extracts, purchase registers, invoice copies, GSTR-2B and GSTR-3B reconciliation, outward supply classification, exemption notifications relied upon, turnover statements, fixed asset register and any voluntary reversals already made. The notice may have one number; the answer requires the route by which that number was reached. Spreadsheets are useful servants but poor witnesses unless the source documents travel with them.
The Rule cannot be bypassed
In Hemraj Rice Mill Private Limited v. Additional Commissioner, CGST and CX, Kolkata North Commissionerate, decided on 12 June 2025, the Calcutta High Court considered a demand for reversal of input tax credit on alleged exempt supplies of by-products. The Court recorded that the adjudicating authority had not followed the procedure in Rules 42 and 43 before confirming reversal and remanded the matter for fresh decision after giving an opportunity of hearing.
The judgment is useful for a reply strategy because it emphasises the statutory method. If a notice treats all credit as attributable to exempt supplies, ignores turnover inputs, or omits the capital goods mechanism, the taxpayer should demonstrate the required computation and specifically identify the departure from the Rules.
Service Tax-era comparison
The earlier CENVAT framework also required disciplined attribution of common credit. In Coperion Ideal Private Limited v. Commissioner of Central Excise and Service Tax, Noida, CESTAT Allahabad, Final Order No. 70456/2018 dated 28 February 2018, a Bench on which I sat examined reversal under Rule 6(3A) of the CENVAT Credit Rules in a Service Tax appeal. The demand had relied on a computation approach that was not the applicable statutory formula during the material period, and the matter was remanded for recalculation under the governing rule.
That Service Tax decision does not decide GST Rule 42 or Rule 43 liability. Applied mutatis mutandis, it supports a narrower proposition: an attribution demand must be computed under the formula in force for the relevant period, using verified inputs rather than an improvised percentage.
Three errors to avoid
Do not treat every exempt receipt as an exempt supply without first examining the statutory character of the receipt. Do not overlook changes in use of capital goods during the relevant period. Do not file only a final reconciliation; provide the invoice, turnover and ledger trail that permits the officer to verify it.
AGS Consulting assists businesses and counsel with Rule 42 and Rule 43 computation reviews, document mapping and reply strategy. For a focused review of an ITC reversal notice and its computation record, contact AGS Consulting.
FAQs
When do Rules 42 and 43 become relevant?
They become relevant where input tax credit relates to both eligible taxable business activity and exempt or non-business use, with Rule 43 specifically addressing common capital goods.
Can the department require reversal without applying the prescribed formula?
A reversal proposal should follow the statutory mechanism applicable to the relevant facts and period. A reply should identify any calculation that departs from that mechanism.
What records matter most in a common credit dispute?
The core records include credit ledgers, purchase invoices, returns, turnover workings, exemption material and, for capital goods, the fixed asset register and usage chronology.
Does earlier CENVAT case law control a GST reversal dispute?
No. It may assist on comparable attribution and computation principles, but GST liability must be tested under Section 17 and Rules 42 and 43.