Hi Pol,

You can use the following

Code:

=IF(MONTH(TODAY())-MONTH(A2)=0,"Current",IF(MONTH(TODAY())-MONTH(A2)=1,"30",IF(MONTH(TODAY())-MONTH(A2)=2,"60",IF(MONTH(TODAY())-MONTH(A2)=3,"90","120"))))

formula in the period column to calculate the due days of debtors:

1. Replace A2 with the cell containing the invoice date.
2. Format the period column as text to avoid any errors.

I hope this helps! Let me know if you have any further questions.