如何将VBA Now()转换为秒来确定整个程序运行时

I'm working on a problem where I need to determine the total time my program takes to execute. First line of code needs to write the current "Start time" and last lines of code need to write the current "End time". Then I'm subtracting "Start time" - "End Time" = Total Time. I'm working on a problem where I need to determ