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A new year, a new numbering sequence for your invoices

Whenever you enter a new year, it’s a great opportunity to reorganise your documents and make a fresh start. Your invoices should be no exception.

Every invoice has a unique invoice number that must be assigned to it. If you use dates or years as a part of your numbering sequence, a new year may mean a fresh start.

Debitoor invoicing software will automatically update your numbering sequence if it can see you’re using the year as part of your invoice numbers

This article explains what the new year means for our Debitoor users and their invoice numbers: Debitoor will either automatically update the numbers for you, or you will need to do it manually. In the following, the different procedures are summarised so you exactly what you’ve got to do.

Debitoor invoicing software learns your invoice number sequence

Debitoor invoicing software is very smart. It can recognise patterns in your invoice numbers and therefore learn your invoice number sequence. This is what allows it to suggest appropriate invoice numbers that are in line with what you already have. This saves you time inputting it every time and can help to minimise mistakes.

Invoice numbers often contain the year that the invoice was issued. We are now reaching the new year, and Debitoor knows this too. As we move into 2021, your invoicing software is therefore going to try and help with this transition where possible.

What happens if you use a date in your numbering sequence?

If your invoice numbers currently contain the year, Debitoor invoicing software will automatically see this and use 2021 as a part in your invoice numbers in the new year. For example, if you’re already using a sequence like:

  • 2020/INV/0001, 2020/INV/0002…
  • 2020-0001, 2020-0002…

Then the system will automatically spot the ‘2020’ and change your sequence accordingly:

  • …2020/INV/0056 > 2021/INV/0001…
  • …2020-0056 > 2021-0001…

This will save you having to manually change your number sequence or risk you forgetting to do it yourself.

Of course, if you do include dates or a year in your invoice numbers, but it’s not so obvious, it may be necessary to change this manually as the system may not recognise that’s what it is.

For example, if you’re using the sequence, ‘INV2020209’, ‘INV2020210’, the system would be likely to simply read this as a number and suggest the number ‘INV2020211’ on January 1st. Therefore, make sure to check the first invoice number Debitoor suggests in 2021 to make sure it’s in line with what you expect.

What happens if you don’t use a date in your numbering sequence?

If your invoice number sequence does not include a date, then you will not see any noticeable change in your numbers after January 1st. Debitoor invoicing software will understand that you have a different type of number sequence and won’t make alterations to it. It will continue to generate what should naturally come next in the sequence you have chosen.

Of course, if you would like to change to your invoicing sequence to a date-based one, you can. Simply edit the invoice number on your invoice template and Debitoor will relearn your preferred sequence.

What about recurring invoices?

If you are already using a year-based number sequence for invoices, recurring invoices are no exception. The system will know what’s going on and make the change to 2021 for you.

If you haven’t already set your invoicing number sequence to one that includes a date and you would like to start doing this for the new year, remember to keep an eye out for any recurring invoices you have scheduled to send.

What to do if a recurring invoice is the first invoice of the new year

If you have been following a different sequence for your invoice numbers, e.g., 001, 002, 003 etc. and you have a recurring invoice scheduled for January 1st, it will naturally suggest ‘004’ as the next invoice.

To get your recurring invoices to start using a new year-based number sequence (if you want), you’ll need to stop the recurring invoice and send it manually, writing the new invoice number in the invoice template. If you don’t, Debitoor will continue to use the old sequence, unaware you wanted to change.

What to do if a recurring invoice is not the first invoice of the new year

If the first invoice you send in 2021 is created and sent manually, you’ll be able to change your numbering sequence however you like in the invoice number field of your template. Your subsequent invoices, including any recurring ones, will follow the new invoicing number sequence you have created.

How to change your invoice number

You can easily edit your invoice number sequence when you create a new invoice with Debitoor's invoice template. Simply click 'New Invoice' and then delete the invoice number the system automatically suggests. Write your new number in the invoice number field.

Picture showing how to edit your invoice number with Debitoor's online invoice template

How can you benefit from a year-based invoice numbering sequence?

Changing your invoicing number sequence to one that includes a date will make it easier for you to keep track of your invoices. Invoices are legal documents, and therefore must be saved for future reference. With all of these documents, it can be easy to get confused.

In the event that your accounting is later questioned, or you have to deal with a customer complaint, including the date in the invoice number will make it easier to retrieve that document at speed. Filing your invoices by year will simplify your accounting and help you to provide superior customer service.


  • If you’ve already included the year in your numbering sequence, Debitoor will automatically make the change to 2021.
  • If you haven’t included the year in your numbering sequence, your numbering sequence will not change.
  • Debitoor recommends you use the year as a part of your invoice number.
  • If you want to change your invoice numbering sequence, you can manually do this by editing the ‘invoice number’ field on your invoice template.