Budget per Year - Does anyone have a solution to dynamically calculate the days per year?

Dear colleagues, Rheinland in Germany

Here I have the challenge to show the budget per year for each project in a project management dashboard. These Dashboad will show the SUM(Budget) for each year. With a project that starts and finishes in the same year, that's easy. How do I deal with a project that starts on 01.09.2016 and ends on 30.04.2019?

I would like to cound the days in the respective year and then calculate these pro rata from the budget. Does anyone have a solution to dynamically calculate the days per year? I would be very pleased about solution suggestions.

Many thanks and many greetings

Andre