System.DateTime truncate Milliseconds

I’ve been trying to make a timer that displays hours, minutes and seconds. I have been using this:

string.Format("{0:HH:mm:ss}", startTime - System.DateTime.Now);

This should only display what I want but it also displays milliseconds. Does anybody know why?

That’s really weird since you aren’t referencing the t value, but DateTime doesn’t need formatting, you can declare the format as a basic .ToString(“format here”)
.Net has a huge documentation about DateTime formatting.