Among different statistical models, the normal model is the most important and widely used statistical model. Normal distribution is used in various fields and in the real world, most natural phenomena follow this distribution. To use the normal distribution in practice and calculate the corresponding probabilities, it is necessary to calculate the cumulative distribution function (CDF) of this distribution. The standard normal cumulative distribution function does not have an explicit form and has an integral form that must be calculated as a numerical integral. In this dissertation, some approximations for the standard normal CDF are discussed. These approximations are then compared with the standard normal CDF. Keywords: Cumulative distribution function, Standard normal distribution, Approximation, Maximum absolute error, Logistic distribution
