Interest rate on GST of March 2020

Santosh Singh (56 Points)

16 June 2020  
Turnover of the entity in FY-2018-19 was nil but in FY-2019-20 is Rs.14 crore.
I just want to know the interest rate on GST liability of March 2020 if paid before June end. And from which date interest will be calculated?

Thanks in advance