JR Pass - 7 or 14 days

Hi there,
I'll be travelling to Japan soon and I am wondering if I should take a 7 or 14 days JR Pass.

I'll spend 2 weeks and here's my itineray:

Tokyo (5 nights) - i will do a day trip to Hakone and probably another one to Nikko
Takayama (3 nights)
Kyoto (5 nights) - i want to do the following day trips: koyasan, Hiroshima
Back to Tokyo for 1 night before leaving for the airport.

Thanks!
Charlotte