The intrinsic rate of natural increase or Malthusian parameter plays a key role fields as diverse as ecology, genetics, demography and evolution. It characterizes the growth of a population in a determinate environment. Since its rigorous statistical estimation requires of intensive calculation, the use of a computer becomes essential. The two main approaches to the calculation of the Malthusian parameter, its error and confidence intervals have been implemented in a program and have been compared by means of an example.