Claiming input tax credit is only half the story. Under several situations, GST law requires you to reverse credit you have already claimed — meaning you add it back to your output tax liability, often with interest. ITC reversal under GST trips up a lot of businesses because it is not one single rule; it is a set of distinct triggers, each with its own logic and its own box in the return.
This guide breaks down the main situations where reversal applies, walks through the two formula-driven rules (Rule 42 and Rule 43), and shows how reversed credit is reported and, in some cases, reclaimed later.
When Does ITC Reversal Apply?
Broadly, reversal is triggered by one of these situations:
- Mixed use of inputs — goods or services used partly for taxable/business purposes and partly for exempt supplies or personal use (Rule 42 for inputs and input services, Rule 43 for capital goods)
- Non-payment to supplier within 180 days of the invoice date — credit claimed must be reversed if payment (including tax) is not made within that window
- Blocked credit under Section 17(5) claimed by mistake — for example, ITC on motor vehicles, employee travel benefits, or club memberships, where the law generally does not allow the credit at all
- Credit notes issued by the supplier that reduce the value or tax on an invoice you have already claimed ITC against
- Capital goods later put to exempt or personal use, even though ITC was fully claimed when purchased
- Switching to composition scheme or opting out of registration, which requires reversal of credit held on stock and capital goods as on that date
Rule 42 vs Rule 43
Both rules deal with apportioning credit between taxable and exempt use, but they apply to different categories of purchases.
| Aspect | Rule 42 | Rule 43 |
|---|---|---|
| Applies to | Inputs and input services | Capital goods |
| Method | Formula apportioning common credit by ratio of exempt turnover to total turnover | Credit spread over a useful life of 60 months; ineligible portion computed monthly |
| Timing | Computed monthly, with a final annual adjustment | Computed monthly for the remaining useful life of the asset |
| Where reported | GSTR-3B Table 4(B)(1) | GSTR-3B Table 4(B)(1) |
The 180-Day Payment Rule, With an Example
If you claim ITC on a purchase invoice but do not pay the supplier — including the GST component — within 180 days of the invoice date, the credit must be reversed along with applicable interest. Once you do make the payment, the credit can be reclaimed.
Example: You receive a ₹2,00,000 invoice (plus ₹36,000 IGST at 18%) from a supplier on 5th January and claim the ₹36,000 as ITC that month. If payment to the supplier is still pending on 4th July (180 days later), you are required to reverse the ₹36,000 in your GSTR-3B for that period, along with interest for the period the credit was held. If you pay the supplier in September, you can reclaim the ₹36,000 in that month's return.
This rule does not apply to supplies under reverse charge or to deemed supplies without consideration, so check the exact carve-outs before applying it mechanically.
How Reversal Is Reported in GSTR-3B
Reversals are captured in Table 4(B) of GSTR-3B, split as:
- 4(B)(1) — reversal as per Rule 42/43 (the routine, formula-based reversals)
- 4(B)(2) — other reversals, including the 180-day rule, blocked credit corrections, and any other reversal not covered by Rule 42/43
Whatever is reversed under 4(B) reduces your net eligible ITC for the month and, if it relates to a genuine reversal rather than a permanent block, can typically be reclaimed later under Table 4(A)(5) once the condition (like payment) is met. Interest, where applicable, is computed separately and paid through the interest ledger, not adjusted against ITC.
Reversal vs Ineligible Credit — Not the Same Thing
It helps to separate two ideas that often get merged in practice. Reversal applies to credit that was validly available when claimed but must be given back due to a later event (non-payment, exempt use, credit note). Ineligible credit under Section 17(5) was never available in the first place — claiming it and later "reversing" it is really a correction of an error, and interest exposure can be treated more strictly in that case. If you are unsure which bucket a specific credit falls into, that is a question for your GST advisor rather than something to guess on.
Common Reversal Situations at a Glance
| Situation | Typical treatment |
|---|---|
| Supplier issues a credit note after you claimed ITC | Reverse the proportionate credit in the month you record the credit note |
| You use office electricity partly for an exempt rental unit | Apportion common input tax credit under Rule 42 |
| Invoice unpaid for over 180 days | Reverse with interest; reclaim on payment |
| ITC claimed on a company car used by staff | Generally blocked under Section 17(5); correct as an error, not a routine reversal |
| Business shifts a floor of its building to a non-business use | Reverse the relevant portion under Rule 43 over the asset's remaining useful life |
Building Reversal Checks Into Your Monthly Close
The most common way businesses miss reversals is simple: nobody is tracking supplier payment ageing against ITC claimed. Before filing GSTR-3B each month, cross-check your accounts payable ageing report for invoices crossing 180 days unpaid, and review any credit notes received. If you are also handling ITC mismatches from GSTR-2B reconciliation in the same cycle, it is worth doing both checks together since they often share the same source data. For businesses managing this across multiple registrations, keeping supplier ledgers organised by GSTIN also helps — see our note on managing multiple GSTINs. As OneBooks GST's accounting software roadmap develops ledger and payables tracking, this kind of payment-ageing check is expected to become easier to run directly from your books rather than a separate spreadsheet exercise.
Frequently asked questions
What happens if I forget to reverse ITC when required?
Unreversed credit that should have been reversed is treated as an incorrect availment, which can attract interest and, in cases of deliberate suppression, penalty. It is generally best corrected as soon as identified, typically in the next return you file, rather than left unaddressed.
Does the 180-day rule apply to advances?
The 180-day payment rule is generally tied to the invoice and the consideration payable against it, including the tax component. Treatment of part-payments and advances can be technical, so verify the specific application with a GST professional or the official portal guidance for your situation.
Can reversed ITC always be reclaimed later?
Not always. Reversal due to non-payment within 180 days can typically be reclaimed once payment is made. Reversal of blocked credit under Section 17(5), however, generally cannot be reclaimed since that credit was never eligible to begin with.
Is interest mandatory on every ITC reversal?
Interest generally applies where credit was availed and utilised, and later needs to be reversed because a condition was not met. The exact interest rate and calculation method can change, so confirm current rates on the GST portal rather than assuming a fixed percentage.
Where do I report Rule 42 and Rule 43 reversals?
Both are reported in Table 4(B)(1) of GSTR-3B as part of your monthly ITC reconciliation, with Rule 42 covering inputs/input services and Rule 43 covering capital goods.
Where OneBooks GST helps
If you handle this at volume, OneBooks GST keeps purchase, sales and bank records reviewable so an ITC difference can be traced back to a source document.
Because OneBooks GST keeps each GSTIN in its own organisation context, a business registered in several states can work through one registration at a time.
