Standard Rate: ₹50/day (taxable) or ₹20/day (Nil).
Amnesty Relief: If you filed during the 2021 window, your late fee was likely capped at ₹500 (taxable) or ₹250 (Nil).
Payment: Use the GST Portal to view the exact, system-calculated amount in the payment section of your GSTR-3B.
Interest: Note that in addition to the late fee, you are liable to pay interest at 18% per annum on the outstanding tax liability (Section 50) for the period of delay.