A quick procedure used to estimate the components in a multicomponent mixture leaving the top and bottom of a distillation column operating with continuous feed. The procedure is applicable to any stage-wise separation process. For a distillation column with a single feed and a total condenser, the fractional recovery of any component in the bottom product is calculated from details that include the reflux ratio, internal flows of liquid and vapour above and below the feed point (i.e., the rectifying and stripping sections), and the relative volatilities of the components. In the calculation, the reboiler counts as stage one.