GSTR 1 is a return filing that must be submitted by every registered dealer, either on a monthly or quarterly, basis depending on their annual turnover. Businesses with sales of up to Rs.5 crore have the option to file quarterly returns under the QRMP scheme which are due by the 13th of the month following the relevant quarter. Taxpayers who do not opt for the QRMP scheme or have a total turnover above Rs.5 crore must file their return every month by the 11th of the next month.