Fine powder BaTiO₃ was prepared using a homogeneous precipitation method. An XRD line-broadening technique was employed to estimate the particle size and microstrain of the powder. The pseudo-Voigt function in variance method and Scherrer formular were used. Both methods were performed with and without correction for instrument broading. The uncorrected data for both methods gave very close results, Value of critical size being 0.11 m m and 0.13 m m for the Scherrer method and variance method, respectively. For the corrected data, the Scherrer method yielded a larger partical size, its critical size being 0.18 while the variance method yielded 0.20 m m.