GST 180-Day Payment Rule: Documents Required During Inspection and ITC Verification

Businesses are increasingly being asked to explain old trade creditors and Input Tax Credit (ITC) during GST scrutiny, audit or inspection. One common focus area is whether the recipient paid the supplier the value of the supply plus GST within 180 days from the invoice date.

However, an unpaid balance in the year-end balance sheet does not automatically prove that ITC must be reversed. The correct review has to be performed invoice by invoice: whether ITC was actually claimed, when the 180-day period expired, how much was paid, whether any reversal was already made and whether the credit was later re-availed after payment.

Important clarification: GST “physical verification of business premises” under Rule 25 and an “inspection” under Section 67 are different legal procedures. There is no separate automatic physical-verification rule merely because a creditor remains unpaid for 180 days. The 180-day compliance can nevertheless be examined during return scrutiny, audit, inspection or another lawful verification.

What Is the GST 180-Day Payment Rule?

The second proviso to Section 16(2) of the Central Goods and Services Tax Act, 2017 requires a recipient—other than for supplies taxed under reverse charge—to pay the supplier both:

• the value of the supply; and
• the tax charged on that supply,

within 180 days from the date of issue of the invoice. Where the payment is not made wholly or partly, Rule 37 requires the recipient to pay or reverse the ITC proportionate to the unpaid amount, along with applicable interest under Section 50, through the prescribed GSTR-3B mechanism.

The 180 days are counted from the invoice date, not from the financial year-end, the balance-sheet date, the contractual credit period or the date on which the accountant begins the review.

Does Every Old Sundry Creditor Require ITC Reversal?

No. A creditor shown in the balance sheet is only a starting point for examination. Each invoice should be placed into the correct category.

Invoice-Wise Working Is Essential

A party-wise closing balance is not enough. One supplier ledger may contain several invoices issued on different dates. Some may be older than 180 days, some may still be within time, some may have been partly paid and some may not have generated any ITC claim.

For every invoice appearing in an old-creditor report, prepare a working containing:

• supplier name and GSTIN;
• invoice number and invoice date;
• taxable value and GST amount;
• total invoice value;
• GSTR-2B appearance and ITC eligibility;
• ITC amount actually claimed and the return period of claim;
• the exact 180th day from the invoice date;
• payments made within and after the 180-day period;
• amount remaining unpaid, including the related tax;
• proportionate ITC requiring reversal;
• GSTR-3B period in which reversal was reported;
• applicable interest and proof of payment; and
• date and return period of re-availment after supplier payment.

TaxClear can assist with accounting and creditor reconciliation and GST return compliance.

Example: Different Invoices of the Same Supplier

Suppose a supplier has a closing balance of ₹20 lakh on 31 March 2026, made up of invoices dated 1 September 2025, 1 December 2025, 1 January 2026 and 1 March 2026.

The accountant should not reverse ITC on the entire ₹20 lakh merely because it appears under sundry creditors. Instead:

1. Check whether ITC was claimed on each invoice.
2. Calculate 180 days separately from each invoice date.
3. Match all payments against the relevant invoices.
4. Identify the unpaid proportion only after the relevant 180-day period expires.
5. Check whether the required ITC was already reversed in GSTR-3B.
6. If the supplier was subsequently paid, verify whether the reversed ITC was correctly re-availed.

An invoice dated 1 March 2026 cannot be treated in the same way as an invoice dated 1 September 2025 merely because both appear in the same balance-sheet creditor balance.

Example: Proportionate ITC Reversal on Partial Payment

Assume an invoice has:

• taxable value: ₹1,00,000;
• GST: ₹18,000;
• total invoice value: ₹1,18,000; and
• eligible ITC claimed: ₹18,000.

If only 50% of the total invoice amount is paid within 180 days and the remaining 50% is unpaid, the Rule 37 reversal is proportionate. On these facts, the ITC attributable to the unpaid half would be ₹9,000, not the entire ₹18,000. Applicable interest must also be examined under Section 50 and the current rules.

The calculation should be based on the amount actually unpaid and supported by invoice-payment mapping. A lump-sum payment in a running vendor account should be allocated consistently with the books, contract and payment references.

Documents to Keep Ready for GST Verification or Inspection

1. Vendor-Wise Creditor Ageing

Prepare a vendor-wise and invoice-wise ageing report, not merely a trial-balance total. It should separately identify invoices within 180 days, invoices exceeding 180 days and payments made after the balance-sheet date.

2. Purchase Register and Tax Invoices

Keep the complete purchase register and original tax invoices readily available. The invoice register should reconcile with the creditor ledger and financial statements.

3. GSTR-2B and GSTR-3B Reconciliation

Show whether each invoice appeared in GSTR-2B, whether the credit was eligible and whether it was actually claimed in GSTR-3B. An invoice on which ITC was never claimed should not be included in a Rule 37 reversal merely because payment is outstanding.

4. Supplier Ledger and Payment Evidence

Maintain supplier ledgers, bank statements, payment vouchers, UTR references and other proof linking each payment to the relevant invoice. Where advances, set-offs or credit notes exist, document their treatment clearly.

5. Proof of Receipt of Goods or Services

Keep goods receipt notes, delivery challans, e-way bills, stock records, service completion records and other evidence applicable to the transaction. These records address the broader ITC conditions, not only the 180-day payment requirement.

6. Rule 37 Reversal Register

Maintain a separate register showing the invoice, ITC claimed, unpaid proportion, reversal amount, applicable interest, GSTR-3B period and payment reference. It should reconcile with the ITC ledger and return workings.

7. Re-Availment Register

If a supplier is paid after the credit was reversed, preserve the payment proof and record the return period in which the eligible ITC was re-availed. Rule 37 permits re-availment after payment of the value of supply plus tax to the supplier.

8. Supplier Confirmations and Reconciliations

A supplier balance confirmation can support the ledger balance, though it does not replace invoice and bank evidence. Resolve differences involving debit notes, credit notes, retention money, discounts and disputed invoices.

9. Exception Documents

Keep separate evidence for supplies under reverse charge and for statutory deemed-payment situations, including relevant Schedule I supplies and amounts covered by Section 15(2)(b), wherever applicable.

10. Written Reconciliation Note

Prepare a concise note reconciling the balance-sheet creditors with:

• invoices on which no ITC was claimed;
• invoices still within 180 days;
• fully paid invoices;
• partly paid invoices;
• credits already reversed;
• later payments and re-availed credit; and
• the final unreconciled amount, if any.

Interest on Delayed Rule 37 Reversal

Rule 37 refers to interest payable under Section 50. The interest position should be computed invoice-wise with reference to the current statutory provisions, the timing of reversal and the facts concerning availment and utilisation of credit. Businesses should not assume that reversing only the principal ITC automatically settles the entire exposure.

Where a delayed reversal or an inspection-related dispute exists, obtain a transaction-specific review before making a payment or submission. For assistance, see TaxClear’s tax notice and legal services.

Re-Availment After Paying the Supplier

Reversal under Rule 37 is not necessarily permanent. If the recipient later pays the supplier the value of the supply along with the tax, the ITC referred to in Rule 37 may be re-availed, subject to eligibility and proper documentation.

The reclaim should be supported by:

• supplier payment proof;
• the original reversal working;
• invoice-wise linkage;
• the reclaim entry in the ITC register; and
• the relevant GSTR-3B working.

Do not reclaim more than the amount actually reversed and subsequently supported by payment.

Physical Verification and Inspection Are Not the Same

Accordingly, taxpayers should ask for and examine the notice, authorisation or communication under which the officer is acting. Do not describe every departmental visit as a Rule 25 physical verification.

Practical Pre-Verification Checklist

• Reconcile total sundry creditors with the general ledger and financial statements.
• Generate invoice-wise ageing from each invoice date.
• Mark invoices where ITC was not claimed.
• Map GSTR-2B, purchase register and GSTR-3B.
• Identify partial payments and calculate proportionate reversal.
• Check delayed reversals and applicable interest.
• Match subsequent payments and ITC re-availment.
• Preserve invoices, bank proof and receipt-of-supply documents.
• Review exceptions separately.
• Keep a signed reconciliation and explanation ready.

Frequently Asked Questions

Does an unpaid creditor automatically mean ITC must be reversed?

No. First confirm that ITC was actually claimed and that 180 days from the invoice date have expired. Reversal applies only to the eligible credit attributable to the amount remaining unpaid, subject to the law and exceptions.

Is the 180-day period counted from the financial year-end?

No. It is counted from the date of issue of the supplier’s invoice.

What if only part of the invoice is unpaid?

Rule 37 provides for proportionate reversal of ITC corresponding to the unpaid amount.

What if ITC was never claimed on the invoice?

There is no claimed ITC to reverse under Rule 37, although the invoice and creditor balance should still be reconciled.

Can ITC be claimed again after paying the supplier?

Yes. Eligible ITC reversed under Rule 37 may be re-availed after payment of the value of supply plus tax to the supplier, supported by proper records.

Does a creditor older than 180 days automatically trigger physical verification?

No. The GST law does not create a separate automatic Rule 25 physical-verification trigger merely because an invoice remains unpaid for 180 days. The matter may, however, be examined during scrutiny, audit, inspection or another lawful proceeding.

Which official provisions should be checked?

Refer to Section 16, Rule 37, Rule 25 and Section 67 on the CBIC Tax Information Portal.

Disclaimer: This article provides general information and does not constitute legal or tax advice. GST treatment depends on the facts, current law, notifications and return disclosures applicable to each taxpayer.