Ruiru's 2021 population is now estimated at 407,129. In 1950, the population of Ruiru was 676. Ruiru has grown by 18,107 since 2015, which represents a 4.65% annual change. These population estimates and projections come from the latest revision of the UN World Urbanization Prospects. These estimates represent the Urban agglomeration of Ruiru, which typically includes Ruiru's population in addition to adjacent suburban areas.