7 or 14 days JR pass

Hello,

may I pls have your advice whether to buy 7 or 14 days JR Pass.
The itinerary:
-From the TOKYO HND to TOKYO -3 days in TOKYO (with some day trips, preliminary Nikko, Fuji) -KYOTO (3-4 days with some day trips to HIROSHIMA, and AMANOHASHIDATE - HOKKAIDO (3-4days) Toya, Noboribetsu - Back to Tokyo, maybe stop in Sendai

Also please, which is the recommended site to check the itineraries and whether JR pass applies, is it https://world.jorudan.co.jp/ ?

Thank you
Ivana