GST late fee and interest on late GSTR-3B and GSTR-1

Every GST-registered business files at least two returns a month or quarter: GSTR-1 for outward supplies and GSTR-3B for the summary and payment of tax. When either is filed after its due date, two separate costs start running – a late fee under Section 47 of the CGST Act and interest under Section 50 on any tax paid late.

Neither can be waived on request, and both must be paid in cash. Knowing how they are worked out helps you decide how quickly to file and what to keep in the cash ledger. For the October 2026 tax period, GSTR-1 is due on 11 November 2026 and monthly GSTR-3B on 20 November 2026.

At a glance

Late fee caps by turnover

The per-day fee stops once it reaches the maximum for your size. These caps, set in June 2021 on the GST Council's recommendation, apply per return to both GSTR-3B and GSTR-1:

Turnover here is the aggregate turnover of the previous financial year. Composition taxpayers filing GSTR-4 have a cap of ₹500 for nil returns and ₹2,000 in other cases. For the annual return GSTR-9 the rules are different – see our GSTR-9 and GSTR-9C guide.

Interest under Section 50

• Rate: 18% per annum, counted from the day after the due date to the date the tax is actually paid.
• Only on cash tax: interest is charged on the portion of tax paid by debiting the electronic cash ledger, not on the part set off from input tax credit.
• Minimum cash balance benefit: if money was already lying in the cash ledger after the due date, the lowest balance in that period is deducted before interest is calculated (Rule 88B).
• Wrong ITC: interest also applies where input tax credit is wrongly availed and utilised – credit that is only availed but not used does not attract interest.

What changed in GSTR-3B from January 2026

From the January 2026 tax period, the GST portal computes interest in Table 5.1 of GSTR-3B itself, giving the benefit of the minimum cash-ledger balance between the due date and the date of payment. Three points matter in practice:

• Non-editable downward: the system figure is the minimum interest payable. You can increase it, but you cannot reduce it.
• Liability break-up from GSTR-1: where tax of earlier periods is paid now, the break-up is auto-populated from the document dates in GSTR-1, GSTR-1A or IFF.
• Cancelled registrations: interest on a late final GSTR-3B is recovered through GSTR-10.

So the old practice of under-reporting interest in GSTR-3B and waiting for a notice no longer works. Check the auto-computed figure before you pay.

Worked example

Example: a Delhi trader with aggregate turnover of ₹1 crore files the October 2026 GSTR-3B on 20 December 2026 instead of 20 November 2026 – a delay of 30 days. Net tax payable in cash is ₹1,00,000, and the lowest cash-ledger balance between 21 November and the date of payment was ₹20,000. For simplicity assume the tax was paid 40 days late.

The GSTR-1 for the same month, if also late, attracts its own fee on the same scale.

The three-year bar on old returns

The Finance Act, 2023 amended Sections 37, 39, 44 and 52 of the CGST Act so that GSTR-1, GSTR-1A, GSTR-3B, GSTR-4, GSTR-5, GSTR-5A, GSTR-6, GSTR-7, GSTR-8, GSTR-9 and GSTR-9C cannot be filed after three years from their due date. The GST portal began blocking such returns in late 2025, and each month another set of old returns becomes time-barred.

If you have unfiled returns from 2023-24, file them now. Once a return is barred, the tax for that period can still be demanded through a notice – with interest and penalty – but you lose the chance to report and pay it yourself.

Checklist to avoid late fee and interest

• Note your dates: GSTR-1 by the 11th, IFF by the 13th (QRMP), monthly GSTR-3B by the 20th; quarterly GSTR-3B for Delhi taxpayers by the 24th of the month after the quarter.
• Keep enough balance in the cash ledger before the due date; a deposit made on time reduces interest even if the return is filed late.
• File a nil return even when there is no business – the ₹500 cap still applies to each missed nil return.
• Pay late fee and interest from the cash ledger; credit-ledger balance cannot be used.
• Clear old pending returns before they cross three years.

How we help

We file GSTR-1, GSTR-3B and annual returns for businesses in Rohini, Pitampura and across Delhi, track due dates and reconcile the cash ledger before filing. See our GST registration and return filing services, the summary of GST changes from 1 November 2026, or our GST notice reply guide if a demand for interest has already arrived.

General information as on 10 November 2026, based on Sections 47 and 50 of the CGST Act, the late-fee rationalisation of June 2021 and GSTN advisories. Rates and caps can change by notification; check the current position or take professional advice before you act.

Frequently asked questions