validity of 7 days pass

Hi there

could you please help me understand when is the 7 days pass validity starting - is it the moment we start using the pass, i.e the time of that specific day, or is it the calendar day at zero hour a.m. of the first calendar day of the pass validity period?

In effect we are planning to buy a 7 days pass and we want to leave from Tokyo to Kyoto, Osaka and Nara over a period of 7 days and effectively travel back to Tokyo within the period of 7 x 24 hours since the start of the first trip, but in the 8th calendar day since the first day of the pass validity period. So - does that mean that we will be out of the 7 days validity period or still within the period ?

thank you
Mihai