Dear Sir,
Hope you are doing well !!
Have you received any notice for penalty?
Late filing attracts penalty called late fee. The late fee is Rs. 100 per day per Act. So it is 100 under CGST & 100 under SGST. Total will be Rs. 200/day*. The maximum is Rs. 5,000. There is no late fee on IGST in case of delayed filing.
Along with late fee, interest has to be paid at 18% per annum. It has to be calculated by the taxpayer on the tax to be paid. The time period will be from the next day of filing to the date of payment.