Amendment in GSTR1

It can be amended maximum by Sept Returns for the following F.Y. or before filling Annual Returns GSTR-9 whichever is earlier. 

You can Amend the mistakes made in GSTR1 of any month in the GSTR1 of subsequent month.

The maximum time limit that has been allowed to Revise the same is the due date of filing of GSTR1 of September of the following year.

For example, mistakes of GSTR1 for the month of February, 2020 i.e. FY 19-20 can be updated till the due date of filing of GSTR1 fir for the month of September, 2020 i.e. FY 20-21.

Thanks