Rennes's 2025 population is now estimated at 371,499. In 1950, the population of Rennes was 123,363. Rennes has grown by 3,057 in the last year, which represents a 0.83% 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 Rennes, which typically includes Rennes's population in addition to adjacent suburban areas.