The present work deals with the accurately determination of the activation energy of crystallization ($E_c$), the frequency factor ($K_o$), the reaction order ($n$) without any approximation for amorphous Se$_{82}$In$_{18}$ glass. Both the $E_c$ and $K_o$ values were determined using Afify, Augis and Bennett and Kissinger methods. In comparison between the three methods one can note that, Kissinger's method isn't suitable to determine $k_0$. This is because that, the $K_o$(Kissinger) is too small compared with that determined by Afify or Augis and Bennett's method. Using the $E_c$ and $K_o$ values the overall reaction rate ($K$) has been calculated as a function of temperature. Where $k$ and $t$ is already known then Avrami's equation can be solved for the unknown quantity which is the reaction order ($n$) as well as recently published. Unlike other methods such as Afify, Augis and Bennett's and others, this method helps one to determine $n$ value without any approximations. The calculated values of the crystallization fraction, $X_{th}$, are in excellent agreement with that determined using the partial area technique experimentally determined, $X_{exp}$.