A GST return filed after its due date costs two things: a late fee for each day of delay, and interest on any tax paid late. The late fee is fixed by law and capped by notification. Interest depends on how much tax was late and for how long. Both are paid in cash.
01Late fee on GSTR-3B and GSTR-1
Section 47 of the CGST Act sets the late fee, and notifications have reduced and capped it. As of October 2026, for GSTR-3B and GSTR-1:
| Return | Late fee per day |
|---|---|
| Nil return | ₹20 (₹10 CGST + ₹10 SGST) |
| Any other return | ₹50 (₹25 CGST + ₹25 SGST) |
Since the June 2021 tax period, the total late fee for one return is capped by your aggregate turnover in the previous financial year:
| Your case | Maximum per return |
|---|---|
| Nil return | ₹500 |
| Turnover up to ₹1.5 crore | ₹2,000 |
| Turnover above ₹1.5 crore and up to ₹5 crore | ₹5,000 |
| Turnover above ₹5 crore | ₹10,000 |
Late fee is charged only under CGST and SGST. A business making only inter-state sales still pays it.
The portal works out the late fee and adds it to the next return, where it must be paid in cash.
02Late fee on other returns
| Return | Late fee |
|---|---|
| GSTR-4 (composition, annual) | ₹50 a day, capped at ₹2,000, or ₹500 for a nil return |
| GSTR-9 (annual return) | ₹50 a day up to ₹5 crore turnover, ₹100 a day above ₹5 crore and up to ₹20 crore, both capped at 0.04% of turnover in the state; ₹200 a day above ₹20 crore, capped at 0.5% |
The GSTR-9 rates apply from the 2022-23 annual return onwards. Businesses with turnover up to ₹2 crore have been exempted from filing GSTR-9 for recent years by notification; check whether the exemption covers the year you are filing.
03Interest on late tax
Section 50 charges interest at 18% a year on tax paid after the due date. Interest is worked out day by day:
Interest = tax paid late in cash × 18% × days late ÷ 365Since an amendment that applies from 1 July 2017, interest for a late return is charged only on the part of the tax paid from the cash ledger. Tax that is set off against input tax credit already in your credit ledger does not attract interest for the delay.
Interest on input tax credit wrongly taken and used is also 18%.
04A worked example
A Rajkot engineering unit with ₹3 crore turnover files its GSTR-3B for August 2026 on 5 October, 15 days after the due date of 20 September. Its tax for the month is ₹3,20,000, of which ₹2,00,000 is covered by credit and ₹1,20,000 is paid in cash.
| Item | Working | Amount |
|---|---|---|
| Interest | ₹1,20,000 × 18% × 15 ÷ 365 | ₹888 |
| Late fee | 15 days × ₹50 | ₹750 |
| Total cost of the delay | ₹1,638 |
If the delay had been 60 days, interest would be about ₹3,551 and the late fee ₹3,000, still under the ₹5,000 cap for this turnover.
A nil return 15 days late costs ₹300.
05A quarterly filer's example
A Varanasi saree retailer under QRMP, with ₹1.2 crore turnover, files GSTR-3B for July to September 2026 on 3 November, 10 days after the due date of 24 October for Uttar Pradesh. Its cash tax for the quarter is ₹45,000.
| Item | Working | Amount |
|---|---|---|
| Interest | ₹45,000 × 18% × 10 ÷ 365 | ₹222 |
| Late fee | 10 days × ₹50 | ₹500 |
The late fee here stays well under the ₹2,000 cap that applies at this turnover, but it would reach the cap after 40 days.
06What else a late return sets off
The money is often the smaller cost.
- Buyers' credit is delayed
- A late GSTR-1 means your invoices reach buyers' GSTR-2B a month late. Larger buyers notice and hold payments.
- E-way bills are blocked
- after two consecutive tax periods without GSTR-3B.
- The next return cannot be filed
- Returns are filed in sequence.
- Registration can be cancelled
- if returns are not filed for a continuous period set by the rules.
- Returns become time-barred
- A return cannot be filed once three years have passed from its due date.
07Interest under QRMP
Quarterly filers under QRMP who use the fixed sum method and pay the PMT-06 challan by the 25th pay no interest for the first two months of the quarter, even if the actual tax was higher. Under the self-assessment method, interest runs on any shortfall from the 26th. See the QRMP guide.
08When the portal's figure looks wrong
The interest shown in Table 5.1 of GSTR-3B is calculated by the system. You can recompute it on the portal if you think it is wrong, for example when part of the tax was paid by challan before filing. Keep the challan receipt and the working.
09Waivers
The government has at times waived late fees for past periods through amnesty schemes, usually with a deadline to file. These are announced by notification and are not automatic. Do not plan around one.
10A simple discipline
An Ahmedabad CA firm with 300 GST clients asks for sales and purchase data by the 5th and follows up on the 10th. Returns are filed on time from whatever is complete, and a supplier bill that arrives late is claimed in the next month. Holding a whole return for one missing bill is a common cause of avoidable late fees.
This guide is general information as of October 2026 and does not amount to tax advice.
MatruOS keeps the month's GST summary ready from your invoices and bills, so the figures for GSTR-3B are in hand before the 20th.