Section 50 explained: this guide covers what it means, who it applies to, the step-by-step process, documents required, fees, due dates and penalties in India — so you can stay compliant with confidence and avoid costly mistakes.
For four years the department computed interest on the gross tax liability of a late return, ignoring the credit balance sitting in the ledger. A retrospective amendment settled it — with two conditions that are easy to miss.
Section 50(1) charges interest at the notified rate — 18% — on tax not paid or paid after the due date. The proviso, substituted by the Finance Act, 2021 with retrospective effect from 01.07.2017: where the return for a tax period is furnished after the due date, except where proceedings under s.73 or s.74 have been initiated in respect of that period, interest shall be payable on that portion of the tax which is paid by debiting the electronic cash ledger. Rule 88B(1) carries the computation.
The three limbs of section 50
s.50(1) — failure to pay tax or any part of it within the period prescribed. Interest at a rate not exceeding 18%, notified at 18%.
s.50(2) — the interest is calculated in the prescribed manner, for the period for which the tax remains unpaid.
s.50(3) — where input tax credit has been wrongly availed and utilised, interest at a rate not exceeding 24%, notified at 18%. Note that this sub-section requires both availment and utilisation. Interest on wrongly availed ITC →
The proviso: two conditions
Condition 1 — the return must be furnished after the due date. The relief applies to a late-filed return. Where a return was filed on time but the liability was under-declared and later corrected, the proviso on its terms does not apply, and interest runs on the shortfall.
Condition 2 — no s.73 or s.74 proceedings initiated for that period. Where the department has commenced proceedings, the relief is withdrawn and interest is computed on the gross liability.
Note that s.74A, which governs FY 2024-25 onwards, was not in the original wording of this proviso. Rule 88B(1) as amended by Notification No. 20/2024-CT includes "or section 74A" in the corresponding exclusion, aligning the rule with the restructured demand provisions.
Rule 88B(1): the computation
"In case where the supplies made during a tax period are declared by the registered person in the return for the said period and the said return is furnished after the due date, except where such return is furnished after commencement of any proceedings under section 73 or section 74 or section 74A in respect of the said period, the interest on tax payable in respect of such supplies shall be calculated on the portion of tax which is paid by debiting the electronic cash ledger, for the period of delay in filing the said return beyond the due date, at such rate as may be notified under sub-section (1) of section 50."
Two features:
"Declared in the return for the said period." The relief covers supplies declared in that period's own return. A supply of March declared in the July return is not covered by the proviso in respect of the March liability.
"For the period of delay in filing the said return beyond the due date." Interest runs from the due date to the date of filing, not to some other date.
The cash-ledger proviso to Rule 88B(1)
"Provided that where any amount has been credited in the Electronic Cash Ledger as per s.49(1) on or before the due date of filing the said return, but is debited from the said ledger for payment of tax while filing the said return after the due date, the said amount shall not be taken into consideration while calculating such interest if the said amount is lying in the said ledger from the due date till the date of its debit at the time of filing return.
So money deposited in the cash ledger before the due date and left there does not attract interest, even though the return was filed late.
The logic: the Government had the money on time. The delay was in filing, not in payment.
This is a real and frequently unclaimed relief. A business that deposits by the 20th but files on the 28th, with the money sitting in the ledger throughout, owes no interest on that amount.
Rule 88B(2): everything else
"In all other cases, where interest is payable in accordance with sub-section (1) of section 50, the interest shall be calculated on the amount of tax which remains unpaid, for the period starting from the date on which such tax was due to be paid till the date such tax is paid."
So for a liability not declared in that period's return — an omission found later, a demand, a voluntary DRC-03 for an earlier period — interest runs on the gross unpaid tax from the original due date to payment. The cash-ledger relief does not apply.
Practical notes
- Deposit into the cash ledger by the due date even if the return will be filed late. It removes interest on that amount entirely.
- Distinguish a late return from an under-declared return. The first gets the net-cash relief; the second does not.
- Check whether proceedings had commenced. Interest computed on gross liability for a period with no s.73, s.74 or s.74A proceedings is wrong.
- The relief is retrospective to 01.07.2017, so a demand for an old period computed on gross liability is challengeable.
- s.50(3) is a different computation — availed and utilised, on the Rule 88B(3) ledger test.
- Interest is payable in cash. The credit ledger cannot discharge it. Order of utilisation →
Key takeaways
- s.50(1): 18% on tax not paid within the prescribed period.
- The proviso, retrospective to 01.07.2017, limits interest to the cash-ledger portion where the return is late.
- The relief is withdrawn where s.73, s.74 or s.74A proceedings have commenced for that period.
- Rule 88B(1) proviso: amounts credited to the cash ledger before the due date and left there attract no interest.
- Rule 88B(2): for anything not declared in that period's return, interest runs on the gross unpaid tax.
- Interest is always payable in cash.
Read next
- Interest on Delayed GST Payment: Section 50
- Interest on Wrongly Availed ITC: Section 50(3)
- Order of Utilisation: Sections 49A, 49B and Rule 88A
- Sequential Filing: Why One Missed Return Blocks Everything
Disclaimer: Positions stated as on 5 September 2026, based on the CGST Act and Rules as amended to 31 March 2026 (ICAI Bare Law, 12th edition).