GST Late Fee Calculator: late fee and interest on GSTR-3B and GSTR-1
Late fee and interest on a late GSTR-3B or GSTR-1, with the cap for your turnover and the cost of each day.
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About the GST Late Fee and Interest Calculator
Pick the return, how you file and the tax period, and the calculator fills in the usual due date. Add the date you filed or plan to file, your turnover band and the tax you pay in cash. You get the days late, the late fee split into CGST and SGST with the cap for your turnover, interest at 18% a year on the tax paid in cash, what each extra day adds and the steps to take today. It runs in your browser and is not tax advice: the GST portal works out the amount you actually pay.
How it works
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Step 1
Choose GSTR-3B or GSTR-1, monthly or quarterly (QRMP) filing, and the tax period. For a quarterly GSTR-3B, pick your State so the due date is right.
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Step 2
Check the due date and change it if the government extended it for your period, then add the filing date, your turnover band, whether it is a nil return and the tax you pay in cash.
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Step 3
Read the late fee, the interest and what one more day adds, follow the steps under the result, and file on the GST portal.
How the late fee is worked out
Section 47 of the CGST Act charges a late fee for every day a return is late. On the GST portal it comes to ₹25 a day under CGST plus ₹25 under SGST for a GSTR-3B or GSTR-1, or ₹10 plus ₹10 for a nil return. Since the June 2021 tax period the fee per return is capped by your aggregate turnover in the previous financial year: ₹2,000 in all up to ₹1.5 crore, ₹5,000 up to ₹5 crore and ₹10,000 above that, or ₹500 for a nil return (Notifications 19/2021 and 20/2021-Central Tax). There is no late fee on IGST or cess.
How interest is worked out
Section 50 charges interest on tax paid after its due date, at the rate the government notifies; CBIC describes 18% a year as the normal rate. When you file a late GSTR-3B, interest on that period's tax is charged only on the part you pay in cash from the electronic cash ledger, not on the part set off with input tax credit. The calculator works it out as cash tax × 18% × days late ÷ 365. Cash that sat in your cash ledger from the due date is left out (rule 88B), and the portal has applied this from the January 2026 tax period.
What this tool cannot do
It works out one return at a time from what you type, and the GST portal's own figure is the one you pay. It does not know about due date extensions or waivers for your period, interest on tax from earlier periods declared later, interest on wrongly claimed input tax credit, or cases where a notice or proceedings have started. It covers GSTR-3B and GSTR-1 only, not annual or other returns. It is not tax advice: check with your CA.
Frequently asked questions
What is the late fee for filing GSTR-3B late?
For a return with tax to pay, ₹50 a day: ₹25 under CGST and ₹25 under SGST. For a nil return, ₹20 a day. The fee stops growing at a cap per return: ₹500 for a nil return, and otherwise ₹2,000, ₹5,000 or ₹10,000 depending on whether your aggregate turnover in the previous financial year was up to ₹1.5 crore, up to ₹5 crore or above ₹5 crore.
Is there a late fee on a late GSTR-1?
Yes. The same daily amounts and caps apply per return, with ₹500 as the cap when you had no outward supplies. The GST portal adds the GSTR-1 late fee to your next GSTR-3B, so you pay it there, in cash.
How is interest on late GST payment calculated?
Interest = tax paid late × 18% × days late ÷ 365. For a late GSTR-3B, only the tax you pay in cash counts, not the part covered by input tax credit. For example, ₹48,500 paid in cash 12 days late carries about ₹287 of interest. The portal fills the interest it works out into Table 5.1 of your next GSTR-3B.
What is the due date for GSTR-3B and GSTR-1?
Monthly filers file GSTR-3B by the 20th of the next month and GSTR-1 by the 11th. Quarterly filers under QRMP file GSTR-1 by the 13th of the month after the quarter, and GSTR-3B by the 22nd or 24th of that month, depending on the State of their principal place of business. The government sometimes extends these dates, so check gst.gov.in for your period.
Can I still file a return that is years late?
Not after three years. Since the Finance Act 2023, a return cannot be filed once three years have passed from its due date, and the GST portal has blocked such returns since 1 December 2025. If a return is close to that limit, file it now, and talk to a CA about any return that is already past it.
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