An inverted duty structure arises when the GST rate on inputs is higher than the GST rate on outward supplies, causing eligible input tax credit to accumulate instead of being fully absorbed against output tax. Section 54(3) of the CGST Act permits refund of unutilised ITC in specified inverted-duty cases, subject to exclusions, notified restrictions and the calculation prescribed in Rule 89(5).
This is not the same as a refund arising from exports. The practical question is whether the accumulation is genuinely caused by the input-versus-output rate inversion and whether the credit entering the formula qualifies as Net ITC under the current rule.
When can an inverted-duty refund arise?
The statutory starting point is Rule 89 of the CGST Rules, read with section 54(3) of the CGST Act. In broad terms, the refund route is relevant where ITC accumulates because the rate of tax on inputs is higher than the rate of tax on output supplies, other than nil-rated or fully exempt supplies, and the case is not covered by a restriction or notified exclusion.
For example, assume a manufacturer buys taxable inputs carrying a higher GST rate and sells a finished product at a lower GST rate. If eligible input credit remains unutilised after normal set-off, the business may have an inverted-duty refund case. The mere existence of an electronic credit ledger balance, however, does not prove eligibility: the reason for accumulation must fit the statutory category.
Inputs and input services are treated differently in the formula
A frequent mistake is to treat all ITC in the ledger as refundable under the inverted-duty formula. Rule 89(5) defines Net ITC for this purpose as ITC availed on inputs during the relevant period, subject to the rule's exclusions. Input-service credit is therefore not simply added to Net ITC in the numerator.
The current formula nevertheless uses total ITC on inputs and input services in the adjustment to the output-tax component. CBIC's Circular No. 181/13/2022-GST explains the 2022 amendment to Rule 89(5), which changed the formula prospectively from 5 July 2022.
Current Rule 89(5) formula
The current rule calculates the maximum refund broadly as the proportionate turnover of inverted-rated supplies multiplied by Net ITC and divided by adjusted total turnover, less an adjusted amount of tax payable on those inverted-rated supplies. The adjustment to tax payable uses the ratio of Net ITC to ITC availed on inputs and input services.
For a working paper, do not rely on a memorised formula from an old return utility or article. Use the live CBIC Rule 89 page because the formula has been amended over time.
Worked illustration
Assume, only for illustration, that during the relevant period a taxpayer has inverted-rated turnover of ₹60 lakh, adjusted total turnover of ₹100 lakh, Net ITC on inputs of ₹9 lakh, total ITC availed on inputs and input services of ₹12 lakh, and tax payable on the inverted-rated supplies of ₹3 lakh.
The first component is ₹60 lakh × ₹9 lakh ÷ ₹100 lakh = ₹5.40 lakh. The adjusted output-tax component is ₹3 lakh × ₹9 lakh ÷ ₹12 lakh = ₹2.25 lakh. On these simplified assumptions, the formula produces a maximum refund amount of ₹3.15 lakh. Actual claims must still satisfy the legal eligibility, ledger, documentary and portal conditions; this illustration is only to show how the mechanics interact.
What records should be reconciled before filing?
- Input invoice data: identify the eligible input credit that forms Net ITC and exclude amounts that do not belong in the formula.
- Input-service credit: keep it separately identifiable because its role in Rule 89(5) differs from input credit.
- Outward supply classification: isolate the turnover of supplies that actually fall within the inverted-rate category.
- GSTR-1 and GSTR-3B: reconcile turnover, tax liability and ITC with the refund working before submission.
- Statement 1/1A data: Rule 89 requires invoice-level statements for claims involving accumulated ITC due to inverted tax structure.
- Electronic credit ledger: ensure the refund claimed is supportable by the credit position and the debit required when the application is filed.
Common mistakes that reduce or delay claims
- Treating every unused ITC balance as an inverted-duty refund.
- Including input-service ITC directly in Net ITC as though it were input credit.
- Using an obsolete pre-July-2022 version of the Rule 89(5) formula.
- Including turnover that is nil-rated, fully exempt or otherwise outside the eligible inverted-rated bucket.
- Ignoring notified restrictions for specified goods or categories.
- Preparing the refund working independently of GSTR-1, GSTR-3B and the underlying invoice register.
How the filing process works
Rule 89 provides for electronic filing of the refund application in Form GST RFD-01 through the common portal. For inverted-duty claims, the rule requires the relevant invoice statement and supporting evidence prescribed for the category. The claim also results in a debit to the electronic credit ledger for the amount claimed as refund.
Businesses should keep a claim file that ties the refund computation to the books, returns, invoice-level input data and outward tax-rate mapping. This makes it easier to explain why the credit accumulated and how each figure in the formula was derived.
Inverted-duty refund versus export refund
Both routes can involve unutilised ITC, but they use different legal triggers and formulas. An export or other zero-rated supply without payment of tax is dealt with under the zero-rated refund framework, while inverted-duty refund is driven by the rate relationship between inputs and output supplies. A taxpayer should identify the correct refund category before building the computation.
Practical takeaway
For an inverted-duty GST refund, start with the cause of accumulation, not the ledger balance. Confirm that the outward supply is eligible, separate input credit from input-service credit, use the current Rule 89(5) formula, reconcile the working to GSTR-1 and GSTR-3B, and preserve invoice-level support. The most reliable primary references are the live CBIC Rule 89 text and Circular No. 181/13/2022-GST.
