Notification Nos. 43 and 44/2018 – Central Tax dated 10th September, 2018, the last dates for filing GSTR1, for the period July 2017 - Sep 2018, was extended to 31st Oct 2018.
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). Maximum late fee Rs 10000 /month.
Also pay 18% per Annum interest for late payment for all outstanding payments.
Late fee is auto calculated by gst portal while submitting returns.