Employee Start date vs calendar year

I have downloaded an Employee attendance record Excel Sheet that keep tracks of days of such as sick day , vacation etc and it seems pretty good.
But currently it goes from January 1st to End of December is there a way to enter a employee date of service date so it goes by that start date rather than the 1st of the year. This way it shows proper vacation and sick time since that’s when most business go by , not the calendar year.

I added some dates by the employee s name but don’t know how to do the formula rather that what it has.

Can anyone help?

Here is my downloaded version