Section 50 and Rule 88B, how interest on GST is actually computed

Three situations, three rules

Section 50 covers three different events, and the working goes wrong when they are mixed:

The rates come from Notification No. 13/2017-Central Tax. Section 50(3) originally carried 24%; Notification No. 09/2022-Central Tax reduced it to 18% with effect from 1 July 2017.

A late return: only the cash counts

Interest on a late return was the most litigated question of the early years: was it payable on the gross tax for the period, or only on the part not covered by credit? The answer, now settled by statute, is the net cash portion.

• The proviso to Section 50(1) says that where the supplies of a period are declared in the return for that period and the return is filed late, interest is payable only on the portion of tax paid by debiting the electronic cash ledger. It was first inserted by the Finance (No. 2) Act, 2019 and then substituted by section 112 of the Finance Act, 2021 with effect from 1 July 2017; Notification No. 16/2021-Central Tax brought that section into force on 1 June 2021.
• Rule 88B(1), inserted by Notification No. 14/2022-Central Tax, repeats the rule and fixes the period: the delay in filing the return beyond the due date.

Worked example. GSTR-3B for April, due 20 May, filed 3 July: 44 days late. Liability ₹10,00,000, of which ₹6,00,000 set off from credit and ₹4,00,000 paid in cash. Interest = ₹4,00,000 × 18% × 44 ÷ 365 = ₹8,679. Interest on the gross ₹10,00,000 would have been ₹21,699, which is the figure the proviso was written to prevent.

Cash already in the ledger by the due date

A second question followed. Suppose the tax was deposited in the electronic cash ledger (by PMT-06) before the due date, but the return, and therefore the debit, came later. Is interest payable for the gap?

From 10 July 2024 the rules answer it. A proviso to Rule 88B(1), inserted by Notification No. 12/2024-Central Tax on the recommendation of the 53rd GST Council, provides that an amount credited to the electronic cash ledger under Section 49(1) on or before the due date and debited while filing that return is not included in the amount on which interest is calculated. Interest runs only on the part of the cash debit that arrived in the ledger after the due date, and only from the date it arrived.

Before 10 July 2024 the courts have divided, and the question is whether the proviso is clarificatory (and so reaches back) or new:

• The Madras High Court (Eicher Motors, 2024; Tamil Nadu State Transport Corporation (Villupuram), 2025) and the Gujarat High Court (Arya Cotton Industries, 2024; Symphony Ltd., 2025; Anas Enterprise, 16.07.2026) have held that a deposit in the cash ledger is payment to the Government, so no interest runs after it, and the Madras High Court treated the proviso as clarificatory.
• The Jharkhand High Court (RSB Transmissions, 2022) took the opposite view: a balance in the ledger is not payment until it is debited against the liability.

Interest on credit: only when it is utilised

Section 50(3) was substituted by the Finance Act, 2022 with effect from 1 July 2017. Interest is now payable only where input tax credit has been wrongly availed and utilised. Credit wrongly taken but reversed before it was used attracts no interest.

Rule 88B(3) settles two practical points:

• The period runs from the date of utilisation to the date of reversal of the credit or payment of the tax, not from the date the credit was taken.
• When credit counts as utilised. Under the Explanation to the rule, wrongly availed credit is treated as utilised when the balance in the electronic credit ledger falls below the amount wrongly availed, and only to the extent it falls below. Where the balance falls because of payment through a return, the date of utilisation is the due date of that return or the date it was actually filed, whichever is earlier; in any other case it is the date of the debit in the ledger.

Worked example. Credit of ₹1,00,000 was wrongly availed in the June return. The credit ledger balance after each return:

If the ₹1,00,000 is reversed on 20 November, interest is charged on ₹30,000 for 61 days and ₹45,000 for 31 days, not on ₹1,00,000 from June.

Interest is payable without a demand

Section 50(1) requires interest to be paid "on his own", and Section 50(2) fixes the period from the day after the due date. It does not wait for a notice. A person who pays tax late through DRC-03 or a later return should pay the interest with it; if the interest is left out, it is recoverable under the demand provisions for the year (Section 73 or 74 up to FY 2023-24, Section 74A from FY 2024-25).

For the working paper

Officer:

• Establish, for each late return, whether it was filed before or after the first notice for the period. That decides between Rule 88B(1) and 88B(2).
• For returns filed from 10.07.2024, exclude cash credited to the ledger by the due date. For earlier returns, note the divided case law and the ledger evidence.
• For credit, trace the credit-ledger balance month by month from availment to reversal; do not run interest from availment.

Practitioner:

• If a return cannot be filed on time, deposit the cash by PMT-06 before the due date. From 10.07.2024 that stops interest on that amount.
• Keep the cash-ledger and credit-ledger statements for every period in which interest is computed; they are the evidence for both computations.

The GSTR-3B late fee and interest calculator applies Rule 88B(1) to a single return on the assumption that the whole cash debit was paid late, and the ITC interest calculator applies Rule 88B(3). A multi-payment calculator that takes the ledger balance on the due date and later deposits into account is planned next.