Rate of a reaction can be expressed by Arrehenius equation as: 

$k=A{\mathrm{e}}^{-E/RT}$

In this equation, $E$ represents

the fraction of molecules with energy greater than the activation energy of the reaction

the energy below which colliding molecules will not react

 the total energy of the molecules at a temperature, $T$

the energy above which all the colliding molecules will react