Copying row to the last empty row and add a new date based on cell value

Hello

I am trying to create a preventive maintanance calendar and I'd like to add activities to a list and set the first inital date in one cell.
When the user has performed the activity they write which date is was performed on and a the row is copied to the last empty row in the list.
A new date is written based on the "Days to next activity"-value.

I have attaced a excel file with the basic idea.
Can anyone help me with the macro code since I am really poor on this.

/Anders

Hi a94andwi,

Please try this code. You can press Alt+F11 to open the macro editor then paste this code in Sheet1 (Blad1):

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this code works fine. But I want the result of the calculation to be hard coded in the last row. Not the formula itself. How do I alter this? And formated in date format as well..
/Anders

So, what's wrong with my macro in post #2 ?

Nothing. I was lazy and tried the last of two excellent solutions. But yours was actually better!!!
Big thanks!!