A recognized shortcoming of the present system of national accounting (the United Nations System of National Accounts) is the omission of nonmarket production from national accounts. Arguably, some of the most important nonmarket production carried out within the home relates to the care of children. This study estimates the monetary value of the childcare provided by parents to children ages 0–13 years in the United Kingdom, exploiting a unique data source that contains information on the amount of time spent on childcare from the perspectives of both parents and children. Using these data, the time input into childcare by parents and the time output of care are both measured and valued. Results at the micro level focus on variation of the imputed value of inputs and outputs of childcare by gender, household structure, and household composition. At the macro level, estimates of the imputed value of childcare are compared to the UK's gross domestic product (GDP).