Raising children takes both time and money. For almost 150 years, scholars have attempted to find convincing ways to capture the costs of raising children. However, even when these estimates include indirect costs, such as mothers’ foregone earnings, little research has been done on estimating the true time costs of raising children. This paper shows how the presence of children changes parents’ use of time. It uses data from the most recent Australian Bureau of Statistics’ (ABS) Time Use Survey to study how the allocation of time differs in households with varying numbers and ages of children and how households with children differ from those with no children. It also examines the intra-household division of time-resources, showing how childcare (and related unpaid work) and parental leisure are distributed between mothers and fathers. Since humans are capable of engaging in more than one activity at a time, the ABS time diaries allow people to report simultaneous activities. A high proportion of time with children is recorded as a ‘secondary’, or accompanying, activity. This paper shows the effect of including secondary activity in the analysis of total parental time commitments, and gives a more accurate picture of the time cost of children than has previously been possible on the basis of analysing ‘primary’ activities alone.