GSTR-3B explained: due dates, late fees and interest

If GSTR-1 is what you sold, GSTR-3B is what you owe. It is the summary return in which you declare your tax on sales, claim the credit for tax on purchases, and pay the difference. Because it is also your payment return, filing it late costs money twice: a late fee for the day count and interest on the tax.

This guide covers the due dates, how the late fee and interest are calculated, the changes of 2025 and 2026, and a worked example.

Due dates

Monthly filers

20th of the next month. For example, GSTR-3B for October 2026 is due on 20 November 2026.

Quarterly filers (QRMP)

If your turnover is up to ₹5 crore and you opted for QRMP, you file GSTR-3B once a quarter. The due date depends on the state of your principal place of business:

Due date	States and union territories
22nd of the month after the quarter	Chhattisgarh, Madhya Pradesh, Gujarat, Maharashtra, Karnataka, Goa, Kerala, Tamil Nadu, Telangana, Andhra Pradesh, Daman and Diu and Dadra and Nagar Haveli, Puducherry, Andaman and Nicobar Islands, Lakshadweep
24th of the month after the quarter	Himachal Pradesh, Punjab, Uttarakhand, Haryana, Rajasthan, Uttar Pradesh, Bihar, Sikkim, Arunachal Pradesh, Nagaland, Manipur, Mizoram, Tripura, Meghalaya, Assam, West Bengal, Jharkhand, Odisha, Jammu and Kashmir, Ladakh, Chandigarh, Delhi

For the first two months of each quarter, QRMP filers pay tax with challan PMT-06 by the 25th of the next month. You can either work out the actual tax (self-assessment) or pay a pre-filled amount based on your last return (the “35% challan”: 35% of the cash tax paid in the last quarterly GSTR-3B, or all of the last monthly one).

Extended due dates are announced by notification; check the GST due dates page for the current calendar.

What is in GSTR-3B

Table	What it holds
3.1	Tax on outward supplies (sales), and inward supplies under reverse charge
3.1.1	Supplies through e-commerce operators under Section 9(5)
3.2	Inter-state sales to unregistered persons, composition dealers and UIN holders, by state
4	Input tax credit available, reversed and net
5	Exempt, nil-rated and non-GST purchases
5.1	Interest and late fee
6.1	Payment of tax, by credit and by cash

Most of tables 3 and 4 are now filled in for you from your GSTR-1 and your GSTR-2B.

What changed in 2025 and 2026

Liability locked to GSTR-1 (July 2025 period onwards). GSTN’s advisory of 7 June 2025 made the tax liability that is auto-filled from GSTR-1, GSTR-1A and IFF non-editable in GSTR-3B. If the figure is wrong, you correct it in GSTR-1A for the same period before filing GSTR-3B, or in a later GSTR-1. A later advisory applied the same lock to Table 3.2.

Three-year limit. Under the Finance Act, 2023, a return cannot be filed more than three years after its due date. The portal began enforcing this from the July 2025 tax period.

Interest calculated by the portal (early 2026). GSTN advisories of 30 January and 20 February 2026 introduced system-calculated interest in Table 5.1. The figure shown is a minimum: you may increase it but not reduce it. The calculation gives credit for the minimum balance held in your electronic cash ledger between the due date and the date of filing, in line with Rule 88B.

How the late fee works

The late fee comes from Section 47 of the CGST Act, reduced and capped by notification. For returns from June 2021 onwards (Notification 19/2021–Central Tax and its state equivalents):

Your case	Per day	Maximum per return
Nil return (no tax payable)	₹20 (₹10 CGST + ₹10 SGST)	₹500
Turnover up to ₹1.5 crore	₹50 (₹25 + ₹25)	₹2,000
Turnover above ₹1.5 crore up to ₹5 crore	₹50	₹5,000
Turnover above ₹5 crore	₹50	₹10,000

Turnover here is the aggregate turnover of the previous financial year. The late fee is counted from the day after the due date to the day you file, and it is paid in cash; input tax credit cannot be used for it.

How interest works

Section 50 of the CGST Act charges 18% simple interest a year on tax that is paid late. When the delay is in filing GSTR-3B, interest is charged only on the part of the tax paid in cash, not on the part set off from input tax credit (proviso to Section 50(1)).

The formula is:

Interest = tax paid in cash × 18% × days late ÷ 365

Worked example

Bose Textiles in Kolkata files monthly. Its turnover last year was ₹1.1 crore. GSTR-3B for September 2026 was due on 20 October 2026; it was filed on 30 October 2026, 10 days late.

Item	Amount
Output tax (CGST + SGST)	₹96,000
Input tax credit used	₹56,000
Tax paid in cash	₹40,000
Late fee: 10 days × ₹50 (below the ₹2,000 cap)	₹500
Interest: ₹40,000 × 18% × 10 ÷ 365	₹197 (rounded)
Total extra cost of a 10-day delay	₹697

In a year with several such delays, this adds up quickly, and late GSTR-3B can also hold up your next GSTR-1, since the portal does not let you file GSTR-1 while the previous GSTR-3B is pending.

If the 57th GST Council’s recommendation is notified as proposed, a business of Bose Textiles’ size that files within the same month (as here, on 30 October) would not pay the late fee; interest would still apply. Until a notification is issued, the normal late fee applies.

Paying the tax

Payment happens inside GSTR-3B. In Table 6.1, the portal first sets off what it can from your input tax credit, in the order the law allows (IGST credit first; CGST and SGST credit never cross over; see CGST, SGST and IGST explained). Whatever remains must be paid from the electronic cash ledger.

Deposit cash with a challan (PMT-06) by net banking, UPI, card, NEFT/RTGS or over the counter, then come back to the return to offset it. The tax is discharged only when you file the return and offset it, so do not stop at the challan. (Cash that was already in the ledger during the delay is taken into account when the portal works out interest, as explained above.) Interest and late fee go in their own heads and are paid in cash too.

Avoiding late GSTR-3B

1. File GSTR-1 first, and check the liability before GSTR-3B opens with it.
2. Review GSTR-2B (and the Invoice Management System) so you claim only credit that is available.
3. Keep cash ready in the electronic cash ledger a few days before the due date.
4. Set reminders for the 20th (or 22nd/24th and the 25th for QRMP).

How software helps

The fastest GSTR-3B is the one where the numbers already agree. Invoiqo’s paid plans give you a GSTR-3B summary built from the same invoices and purchase bills that make your GSTR-1, so the tax liability matches before you open the portal. Your accountant can review it and you file on gst.gov.in.

In short

Monthly: the 20th. Quarterly: the 22nd or 24th, with PMT-06 by the 25th in between. Late filing costs ₹50 a day up to a cap, plus 18% interest on the cash part. Correct your sales figures in GSTR-1A before filing, because the liability in GSTR-3B can no longer be edited. To see which plans include GST return summaries, visit pricing.