The focus of this paper is on young students’ understanding of time which is hardly studied. In the presented study, Swedish 6-year-olds first worked on a task about estimating time and after that they posed their own tasks about time. The research questions concern what aspects of time come to light when 6-year-olds (1) estimate the time needed for specific activities and (2) pose tasks related to time When estimating time, the arguments given by the students were based on previous experiences, personal situations, and emotions. Sometimes more than one of these were used in the same line of argumentation. The tasks posed by the students were related to estimation of a set time, estimation of a time given a specific activity, using a timer, point-of-time, and time as a context. Our study suggests estimation and measurement of time as a suitable content to enlarge students’ understanding of time in addition to the more common focus on ‘telling the time’.