how to furnish the detail in “Table 12. HSN-Wise summary” of GSTR-1 when turnover is below Rs 1.5 Crores? 

Answer  – HSN (Harmonised System of Nomenclature) code is to be filled mandatorily by those registrants whose turnover exceeds Rs 1.5 crores. Furnishing of HSN code at two digit level is necessary for taxpayers having annual turnover above Rs 1.5 cr but upto Rs 5 Cr. Taxpayers having annual turnover above Rs 5 Cr are required to furnish the HSN code at 4 digit level.

But the main question which arises here is that how the summary table shall be filled in case turnover is below Rs 1.5 Cr. In this case HSN code is not required to be furnished, then how the HSN-wise summary of outward supply shall be furnished by assessee ?

If your turnover is below Rs 1.5 Cr then you are not required to furnish the HSN code even in summary table, but then you will be required to provide the description of the item. However, description shall be optional and can be skipped if you are providing HSN code.