If you want a simple way to determine how many days until a certain date, or have a count down clock on your screen, consider the web site days.to. If you go to that link, you can see all the things you can do with the site. If you want to determine how many dates until a certain date, enter https://days.to/dd-month/year. For example, if you want to know how many days until January 1, 2020, enter: https://days.to/1-january/2020
Great little site!