7 day JR Pass is one day short for my travel plan?

Hi,

I'll be in Tokyo in June and plan to leave Tokyo to Kyoto for 4 nights then Hiroshima for 3 nights then back to Tokyo.

I'll activate my JR pass on about 2:00pm on 14 June and go to Kyoto for 4 nights, 14 - 18 June

I'll go to Hiroshima for 3 nights from 18 - 21 June

Will my JR Pass valid to go back to Tokyo on 21 June?

My calculation is by 21 June then it would be 7 days otherwise it's only 6 days if it expires on midnight 20 June?

Thanks
Sonny Giang