as per Section 50 of the CGST interest to be calculated for late payment / short payment/ non payment @18% p.a from due date . However the due dates were keep changed so many times, what is date to be taken for cal of interest
31 March 2019
You need to be considered latest notified due date for late payment of interest .
For example , if due date for payment of tax for the month of Nov 18 is notified as 20th Jan 2019 and you paid tax on 30th Jan 2019 . Due date will be taken as 20 Jan for cal of interest