Hurunui District had a population of 12,558 at the 2018 New Zealand census, an increase of 1,029 people (8.9%) since the 2013 census, and an increase of 2,082 people (19.9%) since the 2006 census. There were 4,926 households. There were 6,369 males and 6,192 females, giving a sex ratio of 1.03 males per female. The median age was 44.4 years; 2,427 people (19.3%) were aged up to 15 years, 1,812 (14.4%) were 15 to 29, 5,841 (46.5%) were 30 to 64, and 2,478 (19.7%) were 65 or older.