panalty on gstr 4

Rs. 50 per day of default, late fees for NIL return is Rs. 20 per day of delay.

I think it is Late fee you are asking?

Late fee for Nil Return - Rs. 20/day (CGST Rs 10 & SGST Rs 10)
Other than Nil return - Rs. 50/day (CGST Rs 25 & SGST Rs 25).

Also pay 18% per Annum interest for late payment for all outstanding payments.

Late fee is auto calculated by gst portal while submitting returns.