Demographers have emphasized the importance of age in explaining the spread of COVID-19 and its impact on mortality. However, the relationship between COVID-19 mortality and age should be contextualized in relation to other causes of death. OBJECTIVE To compare the age pattern of COVID-19 mortality with other causes of death and across countries, and to use these regularities to impute age-specific death counts in countries with limited data. Methods The COVID-19 mortality doubling time in a Gompertz context was compared with 65 major causes of death using US vital statistics. COVID-19 fatality doubling time was similarly compared across 27 countries and used for estimating death counts by age in Israel as a case in point. RESULTS First, COVID-19 mortality increases exponentially with age at a Gompertz rate near the median of aging-related causes of death, as well as pneumonia and influenza. Second, COVID-19 mortality levels are 2.8 to 8.2 times higher than pneumonia and influenza across the adult age range. Third, the relationship between both COVID-19 mortality and fatality and age varies considerably across countries. Conclusions The increase in COVID-19 mortality with age resembles the population rate of aging. Country differences in the age pattern of COVID-19 mortality and fatality may point to differences in underlying population health, standards of clinical care, or data quality.