Markets and public institutions must anticipate evolving care demand driven by East Asia and the Pacific’s exceptionally rapid demographic transition. To this end, this paper develops the Care Simulation Model, a demographic model that estimates gaps in childcare and eldercare needs. By integrating publicly available demographic data, the model captures both care needs and the availability of family caregivers across life cycles and cohorts, allowing the assessment of how demographic shifts may change reliance on family-based care. The paper quantifies unmet family care needs and translates them into estimates of potential market size, defined as the share of households likely to require care services outside the family and the corresponding potential employment creation in childcare and eldercare. By 2030, the childcare needs of an estimated 25 percent of households and the eldercare needs of 7 percent of households in ASEAN-5 countries may not be met within the family. After accounting for family availability and current care employment, the unmet need across 21 countries in East Asia and the Pacific translates into a potential gap of 19.9 million jobs in childcare and 34.1 million jobs in eldercare. The model offers a transparent, cross-country framework to inform care policy, workforce planning, and investment strategies.