GST Invoice number format question on random part

I have a question about generating GST invoice numbers. I have read the exact rule:

a consecutive serial number not exceeding sixteen characters, in one or multiple series, containing alphabets or numerals or special characters- hyphen or dash and slash symbolised as "-'' and "/" respectively, and any combination thereof, unique for a financial year;

But I am not clear on what they mean by multiple series. My account s/w generates sequential invoice numbers but the middle part of the invoice number is random (so that no one can guess the next invoice number). For example, the 15th invoice is 20230727-WXYZ-15 and the 16th is 20230727-AMNO-16. So you see 15, 16 is consecutive but the middle part is random. Is that valid for uploading GST invoices?
 

Replies (6)
Quick Summary
This discussion clarifies the rules for GST invoice number formats in the UK. While the core requirement is a consecutive serial number up to sixteen characters, including letters, numerals, and hyphens/slashes, the use of a random middle section is questioned. The consensus is that as long as the final numerical sequence is consecutive within a financial year, a random element preceding it is permissible. Separate series for different customer types (e.g., online vs. offline) are also allowed, provided each series maintains its own internal continuity.

Yes Its is valid if :
Ater 20230727-WXYZ-15 the Next Bill raised contains Series 20230727-WXYZ-16 & same manner other Series 20230727-AMNO-17.
So that means you cannot break the continuity of bill no. in same Series.
Yes sir

No sir, let me make it clear.

Question 1:

Lets say the previous invoice number is 20230727-WXYZ-15
Can the next invoice number be 20230727-MNOP-16
And after that 20230727-XYZD-17 

and so on. 



 

Question 2:

Lets say I have two series - one for online and one for offline customers -

So for the first and second online customers I generated invoice number 2023/ONLINE/1 and 2023/ONLINE/2

Now, for the third customer who purchased oflline, can I give invoice number 2023/OFFLINE/1  ?
 

1. yes you can . but when you raised any further bill in 3 different series (as per your Example) should be in continuity
ie
In series : 20230727-WXYZ-16
In series: 20230727-MNOP-17
In series: 20230727-XYZD-18

Thank you for your reply but you are getting this totally wrong. As I said multiple times, WXYZ is the random part. It is is not a series. The sequence WXYZ will not appear in any other invoice. It is random. Please try to understand. The last part of the invoice is number sequence (15, 16, 17). But the sequence numbers are prepended by a random sequence of 4 letters as explained above.

 

Also what about question 2?
 

Then No you cannot do so.

Reply to your 2nd Query : yes you can do so.

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