JR Pass

Morning,

I will go to Japan at mid March
From Narita to Osaka (2 day) to Kyoto (1 day) to Tokyo (4 day) and back to Narita.
i just wondering, am i worth it to by JR Pass 7 days?

Yes it will payoff.
Narita Express to Tokyo station + Shinkansen from Tokyo to Shin-osaka + train from shin-osaka to Kyoto + Shinkansen ride back to Tokyo already exceeds the price of the 7-day JR Pass.

Actually, no. The 7 day pass is more expensive than individual tickets and a N'Ex return pass. Plus, you avoid the time and hassle of exchanging the voucher and getting tickets at a counter.

Even cheaper would be to get the eVoucher for Kyoto return and by the Osaka leg separately.

Using eVoucher sounds a wee bit cheaper, but adding your NEX return tickets, and LTD. EXP train to Kyoto and the 4 days JR trains while in Tokyo, and possibility of JR train fares in Osaka, not to mention if you change your mind, and wish to visit any city beyond Osaka (e.g., Hiroshima), or beyond Tokyo (e.g., Nikko)
If I were you, I would not have a second thought of getting the JR PASS.

KIX in, NRT out oneway plan better.
Or no shinkansen take(book) a over night bus.
"Japan Bus Pass" exist.(no valid for railways)
http://willerexpress.com/st/3/en/pc/buspass/

BC Japan Rail Pass valid for "JR" railway mostly.
But those all big cities are not only "JR" tracks.
https://en.wikipedia.org/wiki/Transport_in_Greater_Tokyo
https://ashleeoverseas.files.wordpress.com/2012/01/all-metro-tokyo_tra...
https://en.wikipedia.org/wiki/Transport_in_Keihanshin
https://en.wikipedia.org/wiki/Keihanshin
https://c2.staticflickr.com/4/3432/3372201325_e193bf944c_o.jpg

So Japan Rail Pass will payoff is right
but in this case not so "big" discounted.