The invention is a self-made program in matlab for designing of distillation column. the program is a modular one i.e. it is broken into several functions and in a step wise step determination of tower particulars. it contains about 30 different functions and a main program named as "re4" that enables easy execution of all other functions. the functions also include a list of popular chemicals used in distillation column along with its databank; there is also a provision for addition of data if chemical not present in data bank. the program is been tried to made user friendly by providing provisions for user to enter various varying details such as plate spacing, type of tray, material of construction, type of utility to be used, etc. the program is been designed for four component feed mixture, a binary mixture distillate and a quaternary mixture residue. the program foremost starts calculation with molar liquid and vapor flow rates of enriching section. the program computes tray material balances at the temperature given by user, thus providing the information that whether the given tray temperature corresponds to feed tray or not. similarly, it computes molar liquid and vapor flow rates of stripping section and thus bottom up tray calculations are done. it also gives information about number of trays in enriching as well as stripping section and hence the total number of trays. next it calculates minimum number of trays using popular fug method with eduljee's equation for gilliland's correlation. it also calculates volumetric flow rate of vapor and its flooding velocity with the help of flooding constant that user has to enter from the chart shown; given percentage of downcomer area, it will calculate the tray area and thus the tower diameter. it also calculates the tray efficiency using o'connell's method and actual number of trays based on it. if user wants that it gives an option for cost calculation too. moving to cost calculation it calculates cost of construction of column based on material of construction along with tower dimensions. it correspondingly calculates annual variable cost or precisely operating cost, thus giving the value of total cost. finally, it displays two output files one giving relationship between reflux ratio and theoretical stages and other giving details for cost along with actual number of trays.