Helensville had a population of 2,787 at the 2018 New Zealand census, an increase of 144 people (5.4%) since the 2013 census, and an increase of 255 people (10.1%) since the 2006 census. There were 993 households. There were 1,413 males and 1,377 females, giving a sex ratio of 1.03 males per female. The median age was 36.7 years, with 642 people (23.0%) aged under 15 years, 507 (18.2%) aged 15 to 29, 1,221 (43.8%) aged 30 to 64, and 417 (15.0%) aged 65 or older.