As of 2020, the approximate population of Seoul is 9,733,509.

Nearly 50% of the population of South Korea lives in the Seoul National Capital Area, which includes Seoul and the nearby cities of Incheon and Gyeonggi. As of 2018, the population of the Seoul National Capital Area is estimated to be 25,674,800.

As of 2019, the estimated population of South Korea was 51,709,098.