Saint Andrews is described as a rural settlement by Statistics New Zealand, and covers . It had an estimated population of as of with a population density of people per km2. The settlement is part of the larger Lyalldale statistical area. Saint Andrews had a population of 195 at the
2018 New Zealand census, an increase of 15 people (8.3%) since the
2013 census, and an increase of 18 people (10.2%) since the
2006 census. There were 72 households, comprising 105 males and 90 females, giving a sex ratio of 1.17 males per female. The median age was 50.1 years (compared with 37.4 years nationally), with 30 people (15.4%) aged under 15 years, 27 (13.8%) aged 15 to 29, 102 (52.3%) aged 30 to 64, and 39 (20.0%) aged 65 or older. Ethnicities were 95.4% European, 13.8%
Māori, 1.5%
Asian, and 1.5% other ethnicities. People may identify with more than one ethnicity. Although some people chose not to answer the census's question about religious affiliation, 55.4% had no religion, and 33.8% were
Christian. Of those at least 15 years old, 6 (3.6%) people had a bachelor's or higher degree, and 57 (34.5%) people had no formal qualifications. The median income was $23,900, compared with $31,800 nationally. 15 people (9.1%) earned over $70,000 compared to 17.2% nationally. The employment status of those at least 15 was that 78 (47.3%) people were employed full-time, 24 (14.5%) were part-time, and 9 (5.5%) were unemployed.
Lyalldale statistical area The Lyalldale statistical area includes Saint Andrews and covers . == Education ==