According to Planck: E=hv h=vE
Substituting the dimensions of known physical quantities: [h]=[T−1][ML2T−2]or[h]=ML2T−1
So, SI unit or Planck’s constant is kg m2s-1 which can also be written as (kgm2s−2)×s . But as kgm2s−2 is joule, so unit of h is joule×sec , i.e., Js.