Sac code for small railway e-ticketing agency

Sir, Thx for your reply.

However, if you could explain the calculation then it would be of great help.

GST rate for both SAC codes is 18%.  Kindly tell how it's to be calculated - Whether GST is to be calculated on complete amount received from customer, OR only on my service charges component of the amount.  Eg. - If a customer books a ticket at my shop for Fare= Rs 500 and pays me total Rs. 540 , as Rs. 40 is my agent charge.  So, GST at rate 18% will be calculated on total amount of Rs. 540 ,  OR  only on the commission amount of Rs. 40.

Only on your commission part............i.e. Rs. 40/-

Rs. 500 is just collection on behalf of principal, which has collected GST over the ticket charge itself.

GST registration certificate ( Form- REG-06 ) is issued with applied SAC code - 998551.  However, now I wish to add another SAC code - 998399.

What's the process to add other SAC code to existing GST registration (GSTIN) ?

No need for any change, if all these services are carried under same firm (name).

I run my business under GST registered firm and doing different types of business with multiple SAC codes.

If I want to view which SAC codes I registered for, what's the way ?  I tried to view my profile for my SAC codes, but couldn't find.