There might be various perspectives on the chronological definition for old age, but Koreans consider 65 years or older as old age. The goal of this study was to grasp older adults’ perspective on chronological definition for old age. In order to achieve this goal, the “2018 Seoul Aging Survey” data of 3,034 Seoul citizens over 65 years old were analyzed in this study. According to the 2018 Survey, the citizens responded that the chronological age for old age was 72.5 years in average. The ratio of considering over 75 years old as old age increased from 23.0% in 2016 to 40.1% in 2018. The results of cross tabulation analyses showed that there were statistically significant differences in chronological definition for old age according to the respondents’ age, education level, satisfaction levels of economic status, health status, and leisure activities, and depression level. The more satisfied with their current life the respondents are, the higher levels the chronological definition of old age is. Diverse perspectives on the chronological definition for old age were found among the older adults. For supporting adaptation to later life, the impact of subjective chronological definition for old age on older adults needs to be evaluated.