The aim of the present study was to investigate the processing of proportions, that is, how we perceive the relation between two quantities. When processing the numerical value of a proportion, there exists a congruency effect because not only the numerical value influences the processing procedure, but also the sum of nominator and denominator. This means that we more easily judge a proportion as being numerically larger than another one, if the sum of its components is also larger. Two experiments investigated how the sum of nominator and denominator influenced a proportion comparison task. Adults had to compare two proportions (area of dots) and to identify the numerically larger one. To investigate the influence of the processing speed, in experiment 1 the relevant distance, that is the numerical distance between the values of the proportions, varied between low, medium and high. The irrelevant distance, that is the distance between the sums of nominator and denominator, was kept constant. In experiment 2 the irrelevant distance varied and the relevant distance was kept constant. The results of experiment 1 confirm the numerical distance effect and the congruency effect of the sum of the components. In addition, a systematic influence of the irrelevant information (sum of the components) on the congruency effect was found. Experiment 2 also shows a congruency effect but it was not affected by the variation of the irrelevant distance. These findings demonstrate that the overall size of the components also affects a proportion comparison task.