Trying to figure out how the 7 days works

I plan on being in Japan for a total of 12 days. I'll spend the first 5 nights in Tokyo, and then the remaining 7 days between Kyoto and Osaka. So I was hoping to use a 7 day pass for the days I'm in Kyoto and Osaka. However, I'm wondering if I activate the rail pass on the Friday morning I leave for Kyoto will the pass be active for the full Friday I need to travel home or will it deactivate at the same time I activated it on the prior Friday?