The effects of pressure and hydrogenation, the former causes a lattice contraction while the latter causes an expansion of the sample, have been systematically studied for La Fe13-x Six (x=1.3-2.1). It is found that the typical change of the Curie temperature is ∼150 K when ∼1.6 Hf.u. is absorbed and ∼-106 K as the pressure sweeps from 0 to 1 GPa. One of the most remarkable results of the present work is the presence of a universal relation between Curie temperature and phase volume. The former linearly grows with the increase of lattice constant (∼1510 KÅ), irrespective of how the phase volume is modified. This result implies the exclusive dependence of the magnetic coupling in La Fe13-x Six on the Fe-Fe distances and the interstitial hydrogen does not affect the electronic structure of the compounds.