Abstract: A variable calendar is provided in which the days of the week for several successive weeks are displayed in registry in first and second fixed scales which cooperate, respectively, with first and second sliding scales cumulatively displaying the calendar dates of the days of an entire month and positioned adjacent and parallel to the fixed scales with the spacing intervals of the various scale indicia being identical. The sliding scales are preferably arranged such that the first represents the calendar dates "1" to "15" and the second represents the calendar dates "16" to "31". One sliding scale is offset with respect to the other, i.e., the "16" is in registry with the "2" such that the dates will correlate properly with the days of the week when the sliding scales are positioned relative to the fixed scales.