I put this together for my own application, so I thought I'd share it with the rest of the forum.
https://docs.google.com/spreadsheet/ccc ... 0hTQXd0ZGc
Please click File -> Make a Copy before you edit! I had to leave it editable to allow others to save it and see the forumulas.
Add a line for each day out of the country. It's easy to add lots of lines, then change the date to the above cell +1 if you have lots of trips.
Just make sure the text field is the same for the entire trip if you want the "full days" to calculate correctly. Otherwise overwrite that column.