Most of you would have received your 15 digit provisional ID or GSTIN (Goods and Services Tax Identification Number). Under GST, knowing your GSTIN format like the back of your hand is important. It will help you to ensure that your suppliers have quoted your GSTIN correctly in invoices to you, as your input credit is dependent on this. It will also help you to mention your GSTIN correctly in invoices to your customers, as their input credit is dependent on this.
This is a guide to the GSTIN format, which will make it easier for you to remember it.
1st 2 digits: This is the state code as per the Indian Census, 2011, as given below:
|State code||State||State code||State|
|01||Jammu & Kashmir||19||West Bengal|
|07||Delhi||25||Daman & Diu|
|08||Rajasthan||26||Dadra & Nagar Haveli|
|17||Meghalaya||35||Andaman & Nicobar Islands|
Next 10 digits: This is the PAN of the business entity.
13th digit: This denotes the serial number of registrations the business entity has for business verticals in the state, under the same PAN. It can range from 1-9 for businesses with upto 9 business vertical registrations in the state and for more than 9 registrations, from A-Z. For example, when a business entity gets GSTIN for its 3rd business vertical in the state, this will be 3. When a business entity gets GSTIN for its 13th business vertical in the state, this will be D.
14th digit: This will be ‘Z’ by default.
15th digit: This digit denotes ‘checksum’
Source : http://blogs.tallysolutions.com/structure-of-your-gstin/