In balanced design of experiment sample size is determined to detect a certain standardized size of effect with power 1-$eta$ at the level of significance $alpha$. Tables (Marvin, et al (1970) and Lorenzen and Anderson(1993) and charts (Odeh and Fox(1991)) are available to determine the sample size in balanced design of experiments. To simplify those tables and charts simple MATLAB program is used to find the minimal standardized detectable difference $delta$ when $alpha , eta$ and sample size are given.