The Rolleston urban area had a population of 17,532 at the 2018 New Zealand census, an increase of 8,079 people (85.5%) since the 2013 census, and an increase of 12,582 people (254.2%) since the 2006 census. There were 8,679 males and 8,850 females, giving a sex ratio of 0.98 males per female. Of the total population, 4,536 people (25.9%) were aged up to 15 years, 3,198 (18.2%) were 15 to 29, 8,541 (48.7%) were 30 to 64, and 1,251 (7.1%) were 65 or older.