Survival analyses of longitudinal studies make often use of the Cox proportional hazards model. Mortality differences between risk groups are presented in terms of estimated regression coefficients or relative risks. The research question relates to the presentation of mortality differences in terms of life expectancy differences. The (rest) life expectancy can easily be calculated from the Cox model by using an exponential baseline hazard function. Two example applications for calculating life expectancy differences are presented. One for differences between Body Mass Index classes using data from the Seven-Countries study. The other for differences between physical activity classes using data from the Zutphen Elderly Study. The method can easily be applied to other mortality risk factors.