The result of your conversion between zettajoule and petawatthour appears here
To convert between Zettajoule and Petawatthour you have to do the following:
First divide 1.0e+21 / 3.6e+18 = 277.77777778
Then multiply the amount of Zettajoule you want to convert to Petawatthour, use the chart below to guide you.
Symbol: zJ
No description
Symbol: PWh
No description