In Rentman, number series are used to keep track of different elements. They can be useful for keeping your list of items or documents complete. In this article, we will explain how to edit number series or how to create multiple number series for one document type.

Edit number series

You can change the numbers of many things, for example: equipment items, project numbers and (financial) documents. See the dropdown below for the complete list.

You can edit your number series by going to settings Configuration module > Settings > Number series. The current number of each series is the latest element created of that series. 

By customizing the number series of your documents, you can differentiate between different files. 

Start a new year in your invoice numbers

Many companies include the year in their invoice numbers, for example 2026-0001, 2026-0002, and so on. Rentman does not switch to a new year by itself. You change the number series yourself, ideally just after you send the last invoice of the old year and before you create the first invoice of the new year.

1. Go to Configuration module > Settings > Number series.
2. Under Financial documents, find your invoice series.
3. Update the current number. The current number is the last number used.
4. Click Save.

Best practices

• Plan it for your last working day of the year, or your first working day of the new one, before anyone creates an invoice.
• Update every series you use. If you use separate series for different invoices or companies, each one needs its own new-year number.
• Never set a number that has already been used. Duplicate invoice numbers can cause problems with your accounting and tax administration.
• Keep the same format every year, so your accounting software and accountant can sort invoices easily.
• Check your local rules. Most countries require invoice numbers to follow on from each other without gaps. Restarting at 0001 each year is usually allowed when the year is part of the number. If you are not sure, ask your accountant.

Multiple financial documents series

You can set up multiple number series for your financial documents. This is useful if you want to distinguish between your sales and rental invoices, or if you use Rentman to manage different companies and you want to differentiate their documents. 

To add a new number series:

1. Go to settings Configuration module > Settings > Number series.
2. Scroll down to the section Financial documents and click on the add

3. Type in the name of the series and add a number.

   It is also possible to use letters and symbols in your number series to make them more recognizable. In this case, make sure the number starts with a letter/symbol and ends with a numerical digit.

4. Click  Save  on the top-right corner of the screen.