Know your GSTIN and learn to detect wrong ones to file correct GST Returns

GSTINs are the main constituents of any GST returns you prepare. You can say that they are  the very basis of  filing correct GST return. The errors in filing GST return due to wrong GST numbers can be reduced if we have some idea  of how GST number is defined and what are the rules which guides in defining a GST number.
We usually get GSTIN of the clients via phone or via some hand written note and we fall prey to errors while quoting the wrong GSTIN. So the right way to take GSTIN is by email in well printed format so that there is less scope of error. Otherwise we would hear P as G or E over the phone. 
Know Your GSTIN no. The Structure
Lets see this with this sample GST number in the graphic below. Here even after giving Printed format you can get confused if the first and the last digits are ‘Zero’  or ‘Oo’ and the third last digit is ‘One or’ ‘i’. 
But if you know the simple structure how GST number is being designed then you can reduce the chances of errors. 
The first thing in GSTIN is its structure which everybody should know is that every GSTIN have three parts.
You would notice that first two digits are always numeric and they should be as they are the code of state as per Indian Census 2011. So while entering GST Number it should be kept in mind that ‘zero’ in first or second digit cannot be ‘O’. As  the first two digits would be numeric only.

Second part is 10 digit pan number. If you have PAN number of the party then it can be verified by these ten digits. The most unique thing in this part is that it can be divided in three parts. 
First part is 5 continuous Alphabets, then second part is 4 continuous Numeral  and the third part is one Alphabet. 
So if you are noting down GSTIN then you can counter check that anything in these five digits written as O is actually Oo and not ‘Zero’.
Know your GSTIN, the structure.
The third part consists of three digits. The first digit is numeric as it denotes the number of GST number a particular PAN Card is having in a state. Suppose if a PAN card has two registrations then it would be 2, but in most of the cases it would be 1 only. So another thing which can be sure of is that this would b numeric only and not the alphabet. So the confusion between ‘i’ and ‘One’ can be removed by just looking at it.
The second digit is always ‘Z’ as it has been set by default. But it would be always Alphabet only.
The third digit is actually check some digit which dependent on whole combination of previous digits. And this digit can be both numeric or alphabet. The confusion about this can be removed by Tally itself. 
You must know that Tally itself have the logic the determine if certain GSTIN is right or not. This facility to check the GST number correctness is provided in rel 6.3 and later. The moment you would enter a GSTIN in the field provided by Tally it would give you a warning if it is wrong. The beauty of this feature is that it need no internet to detect correctness. Whereas it would not tell you that if the mentioned GSTIN is of the same company or not. If you enter right GSTIN of a wrong party then it is going to accept it as the format and logic is correct. So be careful.   
Happy Tallying.