Russian and foreign studies consider the stimulation of grandparental labor as a tool to promote an increase in the birth rate, an important scientific task is to assess the potential state costs associated with the reimbursement of the older people’ parental labor costs to their grandchildren. The article proposes two methods for estimating such costs, that allows to solve simultaneously two problems. The first method allows to assess the costs for the formation of an additional child’s human capital and the prolongation of the active longevity of the grandparents. Calculations are made on the basis of existing state measures to compensate for the costs of visiting various types of social institutions. The second method takes into account the time and labor costs of the grandparents in the process of performing the basic functions of parental labor in caring for and looking after grandchildren. The author proposes a mechanism for assigning a payment to the grandparent for assistance in caring for children as an alternative to the institutions of professional assistance to families with children, which are becoming more and more popular, as well as a formula for assessing the potential costs of the state for the implementation of this payment for grandmothers and grandfathers separately.