Invoice Number


I noticed that there’s no locked function (on invoice number prefix) for already created invoices.
For example, I created the prefix - “201401-” and with running number starting with “1”, so it has become “201401-1” which also means Year 2014, Jan, Invoice Number 1.

The issue is, when come end of the month of Feb, I need to change the prefix to “201402-” and the previous invoices created for Jan 2014 has changed from 201401 to 201402.

So there will be a clashed of invoice number. May I know how can I solve this issue?


In your case, invoice prefixes won’t work for you.

They are just static prefixes that are automatically added for display purposes. I’m planning to improve this but for the time being, don’t use invoice prefixes and enter invoice reference number manually.


Thank you for your reply. Noted, for the time being I will not use the prefixes.
Looking forward for the improved version.
Overall, it is a good piece of software. Keep it up.


Due to duplicate invoice numbers I have had to change sequence to A51. When creating a new invoice it defaults to the original invoice number sequence ie 101. Can we change the sequence? or does the same rule apply as the above?


Playing with invoice numbers can be dangerous. If you break sequential invoice numbering, your IRS / HMRC / Tax man could accuse you of hiding invoices and swoop in to audit you.

There’s little benefit to doing ‘clever’ things with invoice numbering. Use prefixing to identify the issuing business unit / company / location or suchlike.


I would also love to be able to use calculated invoice numbers similarly. E.g. yyyyMMddCC where CC = customer number. For now, manually inputting them seem to work.


You would sill have to have a sequential numbering system as part of the invoice number, because your numbering system only works if the customer has only one single invoice per day and even then, your government’s tax inspector will still remain unsure that you are not hiding invoices.

I know it sounds trivial, but this isn’t to be taken lightly. Consecutive invoice numbering is what stands between you and a hefty fine or a costly enforced audit.