GST & Tax
GST Late Fee & Interest Calculator
Late fee for a delayed GSTR-3B, GSTR-1, or GSTR-9, plus interest on unpaid tax.
Rates last verified 2026-09-20 — always confirm against the current notification before filing.
GST Late Fee & Interest Calculator
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₹25 CGST + ₹25 SGST per day, capped at ₹2,000.00
Waiver recommended, not in force. On 8 October 2026 the GST Council recommended waiving the late fee on a section 39(1) return (GSTR-3B) for taxpayers with prior-year turnover up to ₹5 crore who file by the end of the month it was due. It has not been notified, and it does not cover GSTR-1 or GSTR-9. This calculator still uses the current Section 47 slabs until CBIC notifies the waiver. See worked examples.
GSTR-9 for FY 2025-26 is reported open. The portal shows 31 December 2026 as the due date. As reported, GSTR-9 is optional up to ₹2 crore and GSTR-9C is also due above ₹5 crore. The late-fee waiver recommendation does not cover GSTR-9, and the GSTR-9 preset here still uses the current slabs.
How the late fee is worked out
Filing GSTR-3B or GSTR-1 after the due date attracts a late fee — sometimes called a late filing penalty — under Section 47 of the CGST Act, charged per day of delay and split evenly between CGST and SGST. Since June 2021, the per-day rate and the maximum cap both depend on whether the return is nil and, if not, your turnover in the preceding financial year — a small business paying ₹50/day hits its cap far sooner than the fee could otherwise run up. GSTR-9, the annual return, uses a separate turnover-slab table introduced for FY 2022-23 onward, with the cap set as a percentage of annual turnover rather than a flat rupee amount.
Separately, unpaid tax itself accrues interest under Section 50 at 18% per annum, calculated on the tax paid in cash (net of ITC) for every day from the due date to the date of actual payment. This is charged in addition to the late fee, not instead of it — a return filed late with tax still outstanding owes both.
GST return due dates
GSTR-3B is due on the 20th of the following month for monthly filers, or the 22nd/24th (state-dependent) under the QRMP scheme for quarterly filers. GSTR-1 is due on the 11th monthly, or the 13th of the month after the quarter under QRMP. GSTR-9, the annual return, is due by 31 December following the end of the financial year. The late fee clock in this calculator — and the interest, if tax is still outstanding — starts running the day after whichever of these applies to you.
Due in October 2026
| Due | Return | Who files it |
|---|---|---|
| 11 Oct (Sun) | GSTR-1 | Monthly filers, September 2026 |
| 13 Oct (Tue) | GSTR-1 | QRMP filers, July–September 2026 |
| 18 Oct (Sun) | CMP-08 | Composition dealers, July–September 2026 |
| 20 Oct (Tue) | GSTR-3B | Monthly filers, September 2026 |
| 22 Oct (Thu) | GSTR-3B | QRMP filers in Category X states, July–September 2026 |
| 24 Oct (Sat) | GSTR-3B | QRMP filers in Category Y states, July–September 2026 |
| 25 Oct (Sun) | ITC-04 | Principals with turnover above ₹5 crore, April–September 2026 (others file annually) |
Two of these dates fall on a Sunday, and 20 October is Dussehra, a public holiday in most states. None of that moves a GST due date. Only a CBIC notification can extend it, and none has been issued for these returns. If a QRMP filer in a Category Y state files on 25 October instead of 24 October (a Saturday), they're one day late.
Worked example
A GSTR-3B due on 20 August, filed on 5 September with ₹40,000 tax payable in cash, for a business with turnover under ₹1.5 crore: that's 16 days late. Late fee is ₹50 × 16 = ₹800 (₹400 CGST + ₹400 SGST), well under the ₹2,000 cap. Interest is ₹40,000 × 18% × 16 ÷ 365 ≈ ₹315. Total payable works out to roughly ₹41,115 — the original tax, plus late fee, plus interest.
Frequently asked questions
When are GSTR-1 and GSTR-3B due in October 2026?
The GST returns due in October 2026 are 11 Oct (Sun): GSTR-1, Monthly filers, September 2026; 13 Oct (Tue): GSTR-1, QRMP filers, July–September 2026; 18 Oct (Sun): CMP-08, Composition dealers, July–September 2026; 20 Oct (Tue): GSTR-3B, Monthly filers, September 2026; 22 Oct (Thu): GSTR-3B, QRMP filers in Category X states, July–September 2026; 24 Oct (Sat): GSTR-3B, QRMP filers in Category Y states, July–September 2026; 25 Oct (Sun): ITC-04, Principals with turnover above ₹5 crore, April–September 2026 (others file annually). Miss one and the late fee starts the next day: ₹50 a day, or ₹20 a day for a nil return, plus 18% interest on any tax paid late. A due date that falls on a Sunday or a holiday doesn't move unless CBIC notifies an extension.
Is the GST late fee charged even if I have no tax to pay?
Yes — a nil return filed late still attracts a late fee, just at a lower rate (₹20/day total) and a lower cap (₹500 total) than a return with tax liability. Filing on time avoids it even when there's nothing to report.
Do I pay both the late fee and interest?
Yes, they're separate charges. The late fee is a flat penalty for filing the return itself late, split evenly into CGST and SGST. Interest under Section 50 is charged on the actual tax amount you paid late — it applies only when there's tax payable in cash, and runs from the due date until the date you actually pay.
What turnover figure decides my late fee slab?
Your aggregate turnover in the preceding financial year, for GSTR-3B and GSTR-1. GSTR-9's slabs instead use the turnover for the financial year the annual return covers, since the cap is a percentage of that year's turnover rather than a flat amount.
Does this calculator match what the GST portal shows on payment?
It's built from the same notified rates and caps the portal applies, but the portal is the authoritative figure at the time you actually file — always confirm against it before paying, especially if there's any dispute over the exact due date or an amnesty scheme is in effect for that period.