GST Late Fee & Interest Calculator

Late fee for GSTR-3B (and similarly GSTR-1):

• Normal return (with tax liability): ₹50 per day (₹25 CGST + ₹25 SGST), capped at ₹5,000 (₹2,500 each).
• NIL return (no outward supply, no tax): ₹20 per day (₹10 CGST + ₹10 SGST), capped at ₹500 (₹250 each).

The fee runs from the day after the due date to the actual filing date.

Section 50 of the CGST Act: 18% per annum on the net cash tax liability, from the day after the due date until actual payment.

Daily formula: tax × 18% ÷ 365.

Important: post-2021 amendment, interest is on net cash liability (tax paid in cash after ITC adjustment), not on the gross tax. For wrongly availed and utilised ITC, the rate is 24% per annum (a separate, rarer case).

For GSTR-9 (Annual Return): ₹200 per day (₹100 CGST + ₹100 SGST), capped at 0.5% of turnover in the state/UT (0.25% CGST + 0.25% SGST).

The CBIC has from time to time provided lower caps for small taxpayers under amnesty schemes — verify against the latest notification on the CBIC portal.

GSTR-3B: 20th of the next month for monthly filers. Quarterly filers under QRMP file by the 22nd or 24th depending on state group.

GSTR-1: 11th of the next month (monthly) or 13th of the month after the quarter (QRMP).

GSTR-9: 31st December of the next financial year.

The CBIC frequently extends due dates — always check the GST portal before assuming.

No. The GST portal will not accept the return until the late fee is included in the tax payment. The portal computes the fee automatically once you enter the period and the actual filing date.

This calculator gives you the same number in advance so you can budget cash before logging in.

After the 2021 retrospective amendment to Section 50, interest is charged only on the net cash tax liability — the portion of tax that you actually paid in cash after Input Tax Credit (ITC) adjustment.

For example, if your gross tax liability for the month is ₹1,00,000 and you have ₹70,000 of ITC, interest is calculated on ₹30,000 (net cash), not ₹1,00,000. Enter the net cash figure in the calculator above.

For inter-state supplies, IGST is charged instead of CGST + SGST. Late fee and interest follow the same rates — just charged as IGST in a single line rather than split. The total amount is the same as the CGST + SGST sum shown in this calculator.