Updating cell value automatically monthly or weekly etc.

[Cepi1]

Hi

I am wondering if there is a way to update cell value automatically in certain period of time, for example monthly.

I need this because I want to keep track of Customer Lifetime Revenue. We get a certain commission for different apps and services from our customers and the amount is every month the same. So we want to know how much revenue we have got from a customer since the customer relationship started. We have hundreds of customers so it is very hard to manually add the same amount to couple hundred cells.

So just to be sure that my question is understood correctly:

Cell value is now 100

I want to add 10 to it every month, for example first day of the month.

After 6 months the value would be 160 and after 1 year it would be 220. 

And the same thing for all customers so there is couple hundred cells that needs to be automatically updated this way every month. 

Is this possible with Excel?

[#2]

@Cepi1 

My understanding is that you can't do this with Excel alone.  You need some form of trigger mechanism outside of Excel.  Excel on its own cant launch itself and auto-execute code.  If you had this file in OneDrive or Office 365, you could investigate about using the Excel actions to perform the update if it was in a table.  It would be easier if you had some data in a SharePoint list that Flow could easily update, and your Excel just pulls from that data list and refreshes automatically.  

[#3]

If your start date is in B2, you may use this formula in C2 to calculate lifetime revenue:
=DATEDIF(B2,TODAY(),”m”)*10+100

[#4]

@Twifoo 

Sorry I must have misunderstood.  I thought the requester wanted that to happen without even opening Excel and that populated.