Selwyn District had a population of 60,561 at the 2018 New Zealand census, an increase of 15,966 people (35.8%) since the 2013 census, and an increase of 26,916 people (80.0%) since the 2006 census. There were 20,631 households. There were 30,591 males and 29,970 females, giving a sex ratio of 1.02 males per female. Of the total population, 13,452 people (22.2%) were aged up to 15 years, 10,833 (17.9%) were 15 to 29, 29,301 (48.4%) were 30 to 64, and 6,975 (11.5%) were 65 or older.